Background: Silver nanoparticles (AgNPs) are widely used in many daily products either medical or non-medical due to their unique properties. Aim of the work: This study aimed to study AgNPs induced testicular histological alteration in adult male albino rats. Materials and methods: Twenty healthy adult male albino rats were used in this study. They were divided into two groups; group I: control (negative and positive) and group II: AgNPs treated. The animals of the group II were injected intraperitoneally with a daily dose of 50 μg / kg AgNPs. After 4 weeks, all rats were anesthetized and their testes were dissected out carefully and processed for light and electron microscope examinations. Results: H&E sections of AgNPs treated group revealed shrunken disorganized seminiferous tubules lying on irregular basement membrane with marked reduction in the thickness of their germinal epithelium and few spermatozoa in their lumina. Many cells exhibited deeply stained nuclei. The interstitium in-between the tubules was wide and contained homogenous vacuolated eosinophilic material. Ultrastructurely, many cells had irregular shaped nuclei and their cytoplasm contained disorganized mitochondria and many vacuoles. Conclusion: AgNPs had adverse effects on the histological structure of the testis of adult albino rats.