Background: Malaria ranks among the leading global public health challenges. Resistance to insecticides used in vector control by malaria vectors threatens the effectiveness of this intervention. We analyzed data from routine susceptibility tests conducted in sentinel sites in five Ugandan districts to determine the status and pattern of insecticide resistance among Anopheles gambiae mosquito vectors, and to assess the trend of mortality rates of the vector. Methods: We conducted a cross-sectional study using secondary data from sentinel sites in Apac, Kanungu, Hoima, Tororo, and Wakiso Districts of Uganda. Chemicals from different classes of insecticides were subjected to susceptibility tests, which included both the World Health Organization (WHO) standard test kit and the Centers for Disease Control and Prevention (CDC) bottle bioassay tests. Resistance was defined according to the standard WHO criteria of insecticide resistance. The Fisher’s Exact Test was used to determine the difference in mortality rates across years in the study period.Results: A total of eight chemicals were used in the selected districts over the years of study. Out of the 5 districts, we found that the average mortality rate of the mosquito vector by the carbamates was over 98% in 3 districts. In Tororo and Wakiso Districts, the average was about 90%. Mortality of mosquitoes by pyrethroids used averaged less than 80% in all five districts. The organochlorines averaged less than 50% in four out of five districts. In Apac District, organochlorines averaged a mortality rate of 94%. The organophosphates averaged 100% mortality in all sentinel sites. There was no specific pattern in mortality of Anopheles gambiae by insecticides.Conclusion: There was widespread resistance to pyrethroids and organochlorines, with patchy resistance observed against carbamates. Only organophosphates showed potency in all sentinel sites. This threatens gains made in malaria control, and renews calls for continued insecticide resistance monitoring.