Background: A significant environmental health issue is the exposure to polystyrene nanoparticles (PS-PNs), degradation products of plastic waste into nanoparticles (< 100 nm), that are present in soil, water, and the atmosphere. Chronic exposure to PS-PNs produces toxic effects in tissues due to oxidative stress and induced inflammation, ending in organ damage. The aim of current work is to assess possible chronic toxic effects of PS-PNs on testicular tissue, associated mechanisms, and the effect of PS-PNs withdrawal on tissue recovery. Methods: The total experiment period was 6 months, with one month for withdrawal. 28 adult male albino rats were grouped into a negative control, a positive control (given Tween 80), a PS-PNs treated group (given 10 mg/kg orally of Ps-NPs for six months), and a recovery group (given 10 mg/kg orally of Ps-NPs for six months and then left without exposure for a further month). The experiment assessed semen analysis, follicular stimulating hormone (FSH), luteinizing hormone (LH), and testosterone serum levels, malondialdehyde (MDA) and glutathione (GSH) levels in testicular tissue homogenate, and examination of testicular tissue by light microscope. Results of the work showed a decrease in sperm parameters, serum FSH, LH, and testosterone, and testicular GSH and an increase in testicular MDA associated with degradation changes in testicular tissue in PS-PNs treated rats. These changes decreased significantly in the recovery group. Conclusion: PS-PNs have chronic toxic effects on the testis that are reversible after stopping exposure.