diff --git a/AUTHORS b/AUTHORS
index 30e9ddf..81644d0 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -2,3 +2,4 @@ Andrew Lunny (@alunny)
 Anis Kadri (@imhotep)
 Mike Reinstein (@mreinstein)
 Filip Maj (@filmaj)
+Bob Easterday (@bobeast)
diff --git a/lib/pbxProject.js b/lib/pbxProject.js
index 56e0f89..7dfcc48 100644
--- a/lib/pbxProject.js
+++ b/lib/pbxProject.js
@@ -87,10 +87,11 @@ pbxProject.prototype.addPluginFile = function (path, opt) {
     file.plugin = true; // durr
 
     correctForPluginsPath(file, this);
-    file.fileRef = this.generateUuid();
+    
+	file.fileRef = this.generateUuid();
 
-    this.addToPbxFileReferenceSection(file);    // PBXFileReference
-    this.addToPluginsPbxGroup(file);            // PBXGroup
+	this.addToPbxFileReferenceSection(file);    // PBXFileReference
+	this.addToPluginsPbxGroup(file);            // PBXGroup
 
     return file;
 }
@@ -228,8 +229,10 @@ pbxProject.prototype.addStaticLibrary = function (path, opt) {
 pbxProject.prototype.addToPbxBuildFileSection = function (file) {
     var commentKey = f("%s_comment", file.uuid);
 
-    this.pbxBuildFileSection()[file.uuid] = pbxBuildFileObj(file);
-    this.pbxBuildFileSection()[commentKey] = pbxBuildFileComment(file);
+	if (!this.existsInPbxBuildFileSection(file)) {
+		this.pbxBuildFileSection()[file.uuid] = pbxBuildFileObj(file);
+		this.pbxBuildFileSection()[commentKey] = pbxBuildFileComment(file);
+	}
 }
 
 pbxProject.prototype.removeFromPbxBuildFileSection = function (file) {
@@ -245,11 +248,26 @@ pbxProject.prototype.removeFromPbxBuildFileSection = function (file) {
     delete this.pbxBuildFileSection()[commentKey];
 }
 
+pbxProject.prototype.existsInPbxBuildFileSection = function (file) {
+	var retVal = false;
+    var uuid;
+	
+    for(uuid in this.pbxBuildFileSection()) {
+        if(this.pbxBuildFileSection()[uuid].fileRef_comment == file.basename) {
+			retVal = true;
+			break;
+        }
+    }
+    return retVal;
+}
+
 pbxProject.prototype.addToPbxFileReferenceSection = function (file) {
     var commentKey = f("%s_comment", file.fileRef);
 
-    this.pbxFileReferenceSection()[file.fileRef] = pbxFileReferenceObj(file);
-    this.pbxFileReferenceSection()[commentKey] = pbxFileReferenceComment(file);
+	if (!this.existsInPbxFileReferenceSection(file)) {
+		this.pbxFileReferenceSection()[file.fileRef] = pbxFileReferenceObj(file);
+		this.pbxFileReferenceSection()[commentKey] = pbxFileReferenceComment(file);
+	}
 }
 
 pbxProject.prototype.removeFromPbxFileReferenceSection = function (file) {
@@ -272,9 +290,27 @@ pbxProject.prototype.removeFromPbxFileReferenceSection = function (file) {
     return file;
 }
 
+pbxProject.prototype.existsInPbxFileReferenceSection = function (file) {
+    var retVal = false;
+    var i;
+    var refObj = pbxFileReferenceObj(file);
+    for(i in this.pbxFileReferenceSection()) {
+        if(this.pbxFileReferenceSection()[i].name == refObj.name ||
+           this.pbxFileReferenceSection()[i].path == refObj.path) {
+			retVal = true;
+            break;
+        }
+    }
+
+    return retVal;
+}
+
 pbxProject.prototype.addToPluginsPbxGroup = function (file) {
-    var pluginsGroup = this.pbxGroupByName('Plugins');
-    pluginsGroup.children.push(pbxGroupChild(file));
+
+	if (!this.existsInPluginsPbxGroup(file)) {
+    	var pluginsGroup = this.pbxGroupByName('Plugins');
+		pluginsGroup.children.push(pbxGroupChild(file));
+	}
 }
 
 pbxProject.prototype.removeFromPluginsPbxGroup = function (file) {
@@ -288,9 +324,24 @@ pbxProject.prototype.removeFromPluginsPbxGroup = function (file) {
     }
 }
 
+pbxProject.prototype.existsInPluginsPbxGroup = function (file) {
+	var retVal = false;
+    var pluginsGroupChildren = this.pbxGroupByName('Plugins').children, i;
+    for(i in pluginsGroupChildren) {
+        if(pbxGroupChild(file).value == pluginsGroupChildren[i].value &&
+           pbxGroupChild(file).comment == pluginsGroupChildren[i].comment) {
+			retVal = true;
+            break;
+        }
+    }
+    return retVal;
+}
+
 pbxProject.prototype.addToResourcesPbxGroup = function (file) {
-    var pluginsGroup = this.pbxGroupByName('Resources');
-    pluginsGroup.children.push(pbxGroupChild(file));
+	if (!this.existsInResourcesPbxGroup(file)) {
+    	var pluginsGroup = this.pbxGroupByName('Resources');
+		pluginsGroup.children.push(pbxGroupChild(file));
+	}
 }
 
 pbxProject.prototype.removeFromResourcesPbxGroup = function (file) {
@@ -304,10 +355,24 @@ pbxProject.prototype.removeFromResourcesPbxGroup = function (file) {
     }
 }
 
+pbxProject.prototype.existsInResourcesPbxGroup = function (file) {
+	var retVal = false;
+    var pluginsGroupChildren = this.pbxGroupByName('Resources').children, i;
+    for(i in pluginsGroupChildren) {
+        if(pbxGroupChild(file).value == pluginsGroupChildren[i].value &&
+           pbxGroupChild(file).comment == pluginsGroupChildren[i].comment) {
+            retVal = true;
+            break;
+        }
+    }
+    return retVal;
+}
 
 pbxProject.prototype.addToFrameworksPbxGroup = function (file) {
-    var pluginsGroup = this.pbxGroupByName('Frameworks');
-    pluginsGroup.children.push(pbxGroupChild(file));
+	if (!this.existsInFrameworksPbxGroup(file)) {
+		var pluginsGroup = this.pbxGroupByName('Frameworks');
+		pluginsGroup.children.push(pbxGroupChild(file));
+	}
 }
 
 pbxProject.prototype.removeFromFrameworksPbxGroup = function (file) {
@@ -322,9 +387,25 @@ pbxProject.prototype.removeFromFrameworksPbxGroup = function (file) {
     }
 }
 
+pbxProject.prototype.existsInFrameworksPbxGroup = function (file) {
+   var retVal = false;
+   var pluginsGroupChildren = this.pbxGroupByName('Frameworks').children;
+    
+    for(i in pluginsGroupChildren) {
+        if(pbxGroupChild(file).value == pluginsGroupChildren[i].value &&
+           pbxGroupChild(file).comment == pluginsGroupChildren[i].comment) {
+            retVal = true;
+            break;
+        }
+    }
+    return retVal;
+}
+
 pbxProject.prototype.addToPbxSourcesBuildPhase = function (file) {
-    var sources = this.pbxSourcesBuildPhaseObj();
-    sources.files.push(pbxBuildPhaseObj(file));
+	if (!this.existsInPbxSourcesBuildPhase(file)) {
+		var sources = this.pbxSourcesBuildPhaseObj();
+		sources.files.push(pbxBuildPhaseObj(file));
+	}
 }
 
 pbxProject.prototype.removeFromPbxSourcesBuildPhase = function (file) {
@@ -337,9 +418,23 @@ pbxProject.prototype.removeFromPbxSourcesBuildPhase = function (file) {
     }
 }
 
+pbxProject.prototype.existsInPbxSourcesBuildPhase = function (file) {
+	var retVal = false;
+    var sources = this.pbxSourcesBuildPhaseObj(), i;
+    for(i in sources.files) {
+        if(sources.files[i].comment == longComment(file)) {
+            retVal = true;
+            break; 
+        }
+    }
+    return retVal;
+}
+
 pbxProject.prototype.addToPbxResourcesBuildPhase = function (file) {
-    var sources = this.pbxResourcesBuildPhaseObj();
-    sources.files.push(pbxBuildPhaseObj(file));
+	if (!this.existsInPbxResourcesBuildPhase(file)) {
+		var sources = this.pbxResourcesBuildPhaseObj();
+		sources.files.push(pbxBuildPhaseObj(file));
+	}
 }
 
 pbxProject.prototype.removeFromPbxResourcesBuildPhase = function (file) {
@@ -353,9 +448,24 @@ pbxProject.prototype.removeFromPbxResourcesBuildPhase = function (file) {
     }
 }
 
+pbxProject.prototype.existsInPbxResourcesBuildPhase = function (file) {
+	var retVal = false;
+    var sources = this.pbxResourcesBuildPhaseObj(), i;
+
+    for(i in sources.files) {
+        if(sources.files[i].comment == longComment(file)) {
+			retVal = true;
+            break;
+        }
+    }
+    return retVal;
+}
+
 pbxProject.prototype.addToPbxFrameworksBuildPhase = function (file) {
-    var sources = this.pbxFrameworksBuildPhaseObj();
-    sources.files.push(pbxBuildPhaseObj(file));
+	if (!this.existsInPbxFrameworksBuildPhase(file)) {
+		var sources = this.pbxFrameworksBuildPhaseObj();
+		sources.files.push(pbxBuildPhaseObj(file));
+	}
 }
 
 pbxProject.prototype.removeFromPbxFrameworksBuildPhase = function (file) {
@@ -368,6 +478,19 @@ pbxProject.prototype.removeFromPbxFrameworksBuildPhase = function (file) {
     }
 }
 
+pbxProject.prototype.existsInPbxFrameworksBuildPhase = function (file) {
+	var retVal = false;
+    var sources = this.pbxFrameworksBuildPhaseObj();
+    for(i in sources.files) {
+        if(sources.files[i].comment == longComment(file)) {
+            retVal = true;
+            break;
+        }
+    }
+    return retVal;
+}
+
+
 // helper access functions
 pbxProject.prototype.pbxBuildFileSection = function () {
     return this.hash.project.objects['PBXBuildFile'];