Cassava's significance as a food crop is underscored by its ability to thrive in poor soils, withstand drought, and tolerate marginal conditions where other crops might fail. Despite its recognized importance and the introduction of improved cultivars, cassava output in Busia County remains poor, even though it is Africa's most frequently planted staple crop. This study analysed the factors influencing adoption of improved cassava cultivars among 167 smallholder farmers in Busia County, Kenya. The objective was to determine the social and economic factors influencing the adoption of improved cassava cultivars among smallholder farmers in Teso South, Busia County. Data was collected from the sampled farmers using a multistage sampling procedure in six wards. A Binary Logit model was used to investigate the effect of the selected social and economic, factors on the adoption of improved cassava cultivars. The results revealed that the average farm size in Teso South is 2 acres (48.2%), while that set aside for cassava cultivation by households is 0.25 acres (66.4%). Gender, age, marital status and education level did not influence the farm size nor the size set aside for cassava cultivation (p>0.5). Majority 127(76.0%) of the respondents indicated that they had not adopted improved cassava cultivars on their farms (χ2 = 27.04, d.f.=1, p<0.0001). From the study, it was denoted that economic factors such as financial resources, land size and market accessibility positively and significantly influenced the adoption of improved cassava cultivars among smallholder farmers in Teso South, Busia County (β=-0.148, t=-6.886, p<0.001). Social factors such as age, gender, education and household did not influence the adoption of improved cassava cultivars among smallholder farmers in Teso South, Busia County (β=0.011, t=-0.92, p=0.926). The fitting of the model was significant (F 0.05 (3, 163) =29.303, p< 0.001). Agricultural extension programs should focus on providing targeted training and support on innovative techniques and technologies, such as the adoption of improved cassava cultivars, to enhance farmers' capacities and resilience, regardless of their educational backgrounds