Potential exposure of mammals to organophosphate pesticides and their metabolites is recognized (Frank et al. 1991). Organophosphates have been implicated frequently in suboptimal reproductive performance in males and females of various species. Studies have shown that altered androgen metabolism (Krause, 1977), pathological changes in testes and adrenals (Chapin et al. 1988; Oishi et al. 1982; Dunnick et al. 1984), and chromosome aberrations (Kiraly et al. 1979) may be responsible for decreased reproductive performance in animals exposed to organophosphates. Also, organophosphates may have direct effects on sperm fertilizing ability without producing organic changes or altering spermatogenesis (Beck 1953; Harbison et al. 1976). This effect on sperm may occur in the epididymides, seminal plasma, or female reproductive tract.