What is the top priority of a Project Manager?

achieving the project objectives within project constraints

Completion of project on time, within the budget and at the same time ensuring quality.

A PM's top priority should be in leading his team to success. Because when we say success, it includes within time, cost and quality. And co-ordinated team work only can bring success.

I echo with Mohammed Aslam. All efforts of Project Manager should be to complete the project without deviating from the Scope, Cost and Time (schedule) baselines. Alongwith this, he should ensure the project team is happy and motivated at the end of the project...