To determine utility of luteinizing hormone (LH) estimation, post intramuscular (IM) depot leuprolide in comparison with subcutaneous leuprolide stimulation test. Test for monitoring therapy in patients with gonadotropin dependent precocious puberty (GDPP). In seven patients of GDPP, who were treated with 11.25 mg depot leuprolide, the LH peak after subcutaneous (sc) test was compared with LH at hourly interval for 4 h after IM depot leuprolide for 13 tests and 3rd hour value for next ten tests. These two values were compared both before and after therapy. Before therapy, the mean +/- SD LH peak after subcutaneous leuprolide stimulation test was 20.6 +/- 7.85 IU/l (range 9.64-30.4 IU/l), and it was 27.3 +/- 12.21 IU/l 3 h after the first depot leuprolide injection (range 10.5-45.4 IU/l). During therapy, the mean +/- SD of LH peak after sc stimulation test was 1.96 +/- 0.75 IU/l (range 1.1-3.1 IU/l), and it was 2.58 +/- 0.54 IU/l (range 1.4-3.4 IU/l) 3 h after depot leuprolide injection. Three-hour LH value following IM depot leuprolide injection (11.25 mg) can be used for monitoring therapy in patients with GDPP because of its convenience and cost effectiveness.