Pirimiphos-methyl (ACTELLIC^®) is recommended pesticide for control of stored product insects. In this study, pirimiphos-methyl was administered to adult Japanese quail (Coturnix coturnix  japonica) for 21 days at dietary levels of 1/10, 1/100 and 1/1000 LC₅₀. At 1/10 LC₅₀, quail body weight was significantly decreased by 16.86% than that of the control. However, absolute weight of liver from quail exposed to 1/10 and 1/100 LC₅₀ showed significant increases than that of the control. Kidney weight was also increased at the lower concentration, 1/1000 LC₅₀, while showed a significant decrease at the higher concentration, 1/10 LC₅₀. Data of liver function showed a significant increase in levels of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) at concentrations of 1/10 and 1/100 LC₅₀. Also total protein levels were increased at these concentrations. In kidney function parameters, data showed an obvious increase in concentrations of uric acid at 1/10 and 1/100 LC₅₀. However, creatinine concentration was significantly decreased at 1/10 and 1/100 LC₅₀. Moreover, data of sexual hormones showed significant increase in female progesterone and male testosterone at 1/10 and 1/100 LC₅₀, while no significant changes were observed at 1/1000 LC₅₀. The number of egg laying showed significant reduction by 58.6 and 44.8 % at 1/10 and 1/100 LC₅₀, respectively. Based on these results, body weight, clinical signs, and serum biochemical profile findings may be useful parameters for detecting the dietary toxicity associated with the organophosphate pesticides, pirimiphos methyl. In addition, Japanese quail could be an excellent bird model for monitoring the toxicological risks of pesticides in Egypt.