Material & Methods: This study was a descriptive-analytical and practical research. This study tried to measure real and expected time and determined difficulty degree and skills needed for each task of admission department, then determined total work units and needed personnel in admission department of Children's Medical Center affiliated with Tehran University of medical sciences in 2009.

Results: Total work units in admission department were approximately 10780 units for one month. Counting at least 987 units for every person per month, the number of human resources needed for this unit was 11, while current number of human resources in this department is nine.

Conclusion: Finding of this study show that  Children's Medical Center  involves with inadequate human resources and  multiple pressure  due to insufficiency  in mentioned department, and tries to promote the  technology using in this department and increase the personnel and reset the  payment  system based on work load