Malaria vector control interventions in Africa are currently being scaled up in order to attain universal access and appropriate coverage. The aim is to reduce or interrupt disease transmission, and to reach long term goals of malaria elimination and eradication. Currently, in Mozambique the main methods of vector control are indoor residual spraying and long-lasting insecticidal nets. The selection of insecticide resistance is a major concern for the national malaria control programme and its partners, as both these interventions rely on insecticides. This study was designed to evaluate the impact of IRS and ITN programmes implemented in Zambézia province, Mozambique on malaria transmission, through monitoring the vector species abundance, sporozoite rate and insecticide susceptibility. The impact on malaria was measured through parasite prevalence studies. Anopheles gambiae complex and An. funestus group mosquitoes were collected in 23 sentinel sites established in 7 districts in Zambézia province, using windows exit traps. These collections were used to assess abundance, sporozoite rate and transmission index and mouth aspiration catches of females were used for insecticide resistance assays. Identification of An. gambiae s.l and An. funestus s.l and sporozoite detection from the head/thorax were performed using polymerase chain reaction. Plasmodium falciparum prevalence in children aged between 1 and 15 years was assessed using ICT™ malaria rapid diagnostic tests. Annual prevalence was calculated the changes in susceptibility and malaria prevalence in subsequent survey periods compared. Anopheles gambiae s.s, An. arabiensis and An. funestus were the only known malaria vectors found in the study area. Anopheles gambiae and An. funestus were most abundant. Anopheles gambiae s.s and An. funestus were confirmed to be vectors of malaria transmission in the area and the sporozoite rate for both were ranging from 4.1% and 2.3 % in 2006 to 2007 to 1 % to 0 % in 2009-2010 respectively. No infected An. arabiensis were detected. After several IRS rounds with DDT from 2006 to 2009 there was a significant reduction in mosquito abundance and sporozoite rates (P < 0.001), and a reduction in malaria infection as reflected in the overall drop in prevalence from 50% to 32% (P < 0.001). Insecticide resistance assays were carried out using WHO adult diagnostic tests for DDT (4%), lambda-cyhalothrin (0.05%), permethrin (0.75%) and bendiocarb (0.1%). Resistance to carbamate and pyrethroids was first detected in 2010 where high levels of pyrethroid resistance were detected in Mocuba district (76.2 % to lambda-cyhalothrin, 93.5% bendiocarb) and Milange district (lambda-cyhalothrin 82.9% and bendiocarb 84.5%). No DDT resistance was detected during this study. With the change from DDT to lambda-cyhalothrin use for IRS in Zambézia and throughout the country, these findings of insecticide resistance and previously reported data for Mozambique suggest an increased risk to a currently successful malaria control campaign (AU).