Semicarbazide (SEM) is a by-product of azodicarbonamide used to improve the properties of the plastic seals of the glass jar lids of the canned food such as baby food. This work aimed to evaluate the effect of semicarbazide (SEM) on the morphology of testicular seminiferous tubules of juvenile albino rat. Twenty juvenile male albino rats aged 4 weeks were divided into two main groups: group I (control), group II (treated with SEM 40 mg/kg oral daily for 4 weeks). Specimens from the testes were processed for different histological examinations, histochemical staining with Periodic Acid Schiff (PAS) and immunohistochemical study using antibodies against Bcl-2 was carried out in addition to morphometrical and statistical analysis. SEM-treated group showed some vacuolated spermatogenic and Sertoli cells, discontinuity of germinal epithelium, some exfoliated spermatogenic cells in the lumen in addition to focal loss of the basement membrane. A statistically significant decrease in both mean epithelial height and area percentage was recorded in group II. A statistically significant decrease of PAS reaction of the basement membrane was observed. A statistically significant decrease in Bcl-2 positive cytoplasmic immunoreaction in cells of seminiferous tubules was detected. Electron microscopic examination revealed swollen mitochondria, dilated rough endoplasmic reticulum, vacuolated cytoplasm and areas of cytoplasmic loss in spermatogenicand Sertoli cells. The nuclei of some primary spermatocytes and spermatids appeared dark and shrunken or fragmented. Thickened basement membrane with collagen deposition was detected. It could be concluded that SEM causes significant structural changes in juvenile seminiferous tubules of rat testis.So, it is recommended to use alternative safe substance in the sealing process of glass jar lids.