This study was designed to investigate the effects of long term administration of Artmether/Lumenfantrine on semen quality and histology of the testis in albino mice. This study lasted for twenty-three (23) days, within which the mice were acclimatized, inoculated with Plasmodium berghei parasite, administered with Artemeter/Lumenfantrine and sacrificed. A total of twenty five (25) mice were used for the study and were grouped into five groups (n=5) with five mice per group. All the mice were fed with rat chow and clean drinking water, under regulated environmental factors such as temperature. Group ‘A’ mice were used as the control mice. Group ‘B’ mice were infected with malaria. Group ‘C’ mice were infected with malaria and treated once with 56mg/kg of Artemether/Lumenfantrine. Group ‘D’ mice were infected with malaria and treated twice with 56mg/kg of Artemether/Lumenfantrine. Group ‘E’ mice were infected with malaria and treated thrice with 112mg/kg of Artemether/Lumenfantrine. The drug was administered to the animals as solution using orgastric tube. The dosage was 56mg/kg Artemether/Lumenfantrine administered twice daily between an 8-hour interval for two days. This treatment of malaria was done on three occasions, which connoted the short-term, middle-term, and long-term administration of Artemether/Lumenfantrine. Upon sacrificing the mice, to show the effect of long term administration of artemether/ lumenfantrine on semen quality and histology of the testis the results were rendered using ± SEM and statistically analyzed using ANOVA with significant level (p<0.05). Comparing the results, of a normal albino mice and infected malaria albino mice showed significant decrease (p<0.05) when compared to control group. However, it is noteworthy that long term administration can decrease the quality of semen and the histology of the testis..