Background: The blowflies of Chrysomya albiceps are of medical and forensic importance because larvae of C. albiceps are the insects that are most commonly associated with corpses. Tramadol is a widely abused opioid with increased cases of overdose. Purpose: To evaluate the effect of tramadol on C. albiceps larvae and to determine tramadol level in the third larval stages of C. albiceps reared on tissue containing tramadol. Methods: C. albiceps was reared on rabbit tissues administered tramadol (30.8 mg/kg dissolved in distilled water) by intraperitoneal injection twice daily for one week. The control group was reared on rabbits injected with distilled water. The third larval instar of C. albiceps was studied using scanning electron microscope. Biomorphic data (weight, length, and width) of larvae were documented and compared to those of the control group. Tramadol concentrations in postmortem livers, kidneys, and muscles from both treated and control groups were analyzed by high performance liquid chromatography (HPLC) immediately after scarification of rabbits. Results: Significant differences in the means of larval weights, lengths, and widths of tramadol and control group were observed. Ultrastructure changes were also detected in the tramadol reared group in the form of a dense compressed irregular shape larval body and deformed anterior and posterior ends. The concentration of tramadol in the third larval stage was 29.62 µg/g, a level that was comparable to postmortem tissue concentration. Conclusions: The study established the effect of tramadol on the morphology of third larval instar of C. albiceps. These results indicate that tramadol retards larval development, thus interpretation and application of insects' data should be used with caution in forensic entomology when tramadol is suspected as a cause of death.