Project manager and line manager interface refers to working relationship between project manager and line manager. This interface works to get project activities accomplished within constraint of limited time, allocated cost and specified quality performance.

Project managers depend on line managers. When the project manager gets in trouble, the only place he can go is to the line manager because additional resources are almost always required to alleviate the problems. When a line manager gets in trouble, he usually goes first to the project manager and requests either additional funding or some type of authorization for scope changes.

Project mangers control only those resources which are temporarily loaned by line managers. S/he reminds the line managers that there are also time and cost constraints of the project. This is the starting point for better resource control. Therefore project manager must negotiate with all line mangers for pooling require resources on time.

Interface between project manager and line manager takes place for following purposes:

• To get needed resources from functional department on time.
• To get good support of line managers while negotiating with various parties in connection with project work.
• To achieve harmonization between project works and line department's work.
• To get technical and managerial assistance.
• To solve the project related problems.

Project's success mainly depends on working relationship between project manager and line manger. So there must be better coordination, reporting, communication and negotiation between them for good working relationship and for the betterment of the project.