The current study explore the effect of the organophosphorus compound (dimethoate ) on male reproductive efficiency, tissue residues and its pathological picture. Dimethoate was given either directly to albino rats at dose |level 1/10, 1/20, 1/40 of LD5O and also give with green sprayed forage along 65 consecutive days. The results indicated that dimethoate altered the biochemical parameters of serum indicating liver and kidney dysfunction. Also semen picture and the weight of male sexual organs (testes, prostate and seminal vesicle) together with lower testosterone level gave indication for lower reproductive efficiency Tissue dimethoate residues were detected in liver, tests and skeletal muscles. Concerning to pathological findings dimethoate induced degenerative changes in liver, kidneys and heart in the form of cloudy swelling, vacuolar and hydropic degeneration. Focal areas of hemorrhages and necrosis were also seen in liver and kidneys. Vascular lesions in the form of congestion, thromboss and necrosis of blood vessels as well as perivascular mononuclear infiltration were also pronounced. The mostly affected organs were brain and testes especially in rats given dimethoate contaminated feed. These changes included vesiculation in the brain tissue. encephalomalacia as well as satellitosis and neurophagia. The tests showed atrophy of seminiferous tubules together with fibrosis, intertubular edema and failure of spermatogenesis. We advice that a great attention should be taken when dealing with such insecticides in order to avoid its various adverse action on different body tissue