Abstract: Extensive use of insecticides contaminated the agricultural products and environment. Current study aimed to (1) Determine residue quantities of chlorpyrifos-methyl (CPM) in tomato fruits and (2) Evaluate the toxicity of the residue amounts of CMP in tomato to white albino rats. Results revealed that the residue of CPM (after 1 h of application) was 4.05 mg kg–1 and decreased from 3.73-1.74 mg kg–1 after 1-21 days post application. The half-life time of CPM in tomato fruits was 11.99 days. The toxicological effects of residue quantities were studied through administering rats with residue amounts that were detected after 1, 7, 14 and 21 days post application. Highlighted toxic effects were reduction in activities of lactate dehydrogenase (-58.13% of control) and aspartate transaminase (-39.8% of control) and increase in alkaline phosphatase (61.6% of control) and γ-glutamyl transferase (35.6% of control) enzyme activities. Pesticides is a requirement to control plant pests, so, it is crucial to follow safety guidelines of pesticides usage and to harvest plants after the time that bring no harmful effects to people.