Ossimi is the most abumdant breed of sheep in Egypt. As compared with other sheep, the age of puberty and reproductive capacity of this local breed received little attention. For both purposes, gonadal and epididymal sperm counts were studied in 48 healthy slaughtered growing Ossimi ram lambs. Animals were classified into 8 equal age groups (6, 7, 8, 12, 15, 18, 24 and >24 month). Testis and epididymis (caput, corpus and cauda) of one side were dissected and weighed separately. The whole testis and each region of epididymis were cut seperately into small pieces then homogenized with known volumes of saline using an electro mixer. To 5 ml of each homogenate, 3 drops sodium hydroxide (2%) and 2 drops eosin solution (3%) were added and gently mixed. Stained sperm heads, without elongated spermatids, were counted twice with a cytometer. At 6 months, no sperm could be detected from any organ while at 7 months 2 cases had sperm in their testes only. In both cases testicular weight, sperm per g tissue and total sperm per gonad averaged 48.5 g, 23.6 x106 and 1.14 x109 sperm respectively. At 8 months, sperm were detected from all testes and epididymes. At this age, testis weighed 51.3±1.8 g, while sperm count per g tissue and per organ were 26.1±4.2x106 and 1.34±0.23 x109 respectively. Moreove, total sperm count in epididymis was 1.64±0.19x109. After this age, testes and their total sperm counts showed significant increases (P<0.01) until 24 months. However, number of sperm per g tissue was maximum at earlier age (15 months) and reached 90.2±7.9x109. Epididymis (weight and total sperm) developed slowly from 7 to 12 months then rapidly until 24 months. Each region of epididymis grew independently. Ratios of caput and corpus weights to whole epididymis were 41.3% and 20% respectively at 8 months. These ratios decreased to 39.7% and 13.6% at 18 months, respectively. Ratios recorded for cauda increased from 38.7% to 46.7% at the same ages, respectively. There were similar trends for sperm counts. At 24 months, cauda contained 45.15±7.9 x109 sperm representing 80.7% of total epididymal sperm. Significant correlations (P<0.01) were present between testis-epididymis weights and their sperm counts. It is evident that Ossimi ram lambs reached puberty at 7-8 months of age while maximum reproductive capacity attained at 2 years. Data obtained might be of value in rams selected for breeding especially with regard to evaluate the size of testes and cauda epididymedes