In Kenya, value addition in Irish potatoes provides farmers with substantial income. However, the adoption of value addition practices is still low among farmers. Currently, there is a dearth of information on the factors affecting the adoption of value addition practices among smallholder Irish potato farmers in Bomet County. Using single cross-sectional data from 200 randomly selected respondents, the study determined factors affecting the uptake of value addition practices using the Binary logistic regression model. Descriptive statistics show that the majority of the Irish potato farmers (62.5%) adopted value addition practices. It was also found that the majority of the farmers did not attend training, and were not accessing agricultural extension services and credit facilities. Logistic regression results show that group membership (P = 0.013), cost per unit of potatoes (P = 0.041), and total land size (P = 0.058) were key variables that significantly influenced adoption of value addition. From the results, it is critical for farmers to join farmer groups and increase acreage under Irish potato production to reduce cost per unit. Farmers should also adopt modern value addition technologies to be encouraged to reduce post-harvest losses of potatoes and to improve smallholder farmers’ income.