Abstract Excitation functions of (α, xn) reactions on 98.28% enriched 123Sb and on natSb were measured from 9 to 40 MeV. The data could be described well in terms of statistical and precompound models using the code TALYS. The discrepancies in the literature data for the formation of 125I and 126I were solved. The nuclear reaction 123Sb(α,3n) 124I on an enriched target appears to be interesting for the production of 124I ( T 1/2=4.18 d) over the energy range E α=42→32 MeV, its yield being 11.7 MBq/μA h. The levels of the radionuclidic impurities 125I and 126I amount to 1.8% and 0.6%, respectively. The use of natSb as target material for 124I production is unsuitable due to the high level of 123I impurity.