Effects of four seed dressing chemicals on seed storability of three soybean varieties were evaluated by probit modelling. Seeds treated with fungicides and/or insecticides, viz., Apron Plus, Fernazan D, Almithio and Aldrex T at manufacturer’s recommended doses, along with control lots were stored under ambient conditions for six months. Results show that seed dressing reduced deterioration for two months in M-351 and three months in ‘Samsoy 1’and TGX 1740-3F. In particular, seeds treated with Apron Plus, Almithio and Aldrex T showed significantly longer storage life than untreated seeds, except for the variety M-351. Probit analysis also indicated negative slopes (1/) implying that some deterioration occurred irrespective of the seed lots and dressing treatments. Furthermore, no chemical was able to completely arrest seed deterioration, and so cannot replace conditioned storage, especially if storage exceeded three months. Nevertheless, these treatments will benefit small-scale producers, with low carryover stocks and no resources for advanced conditioned storage.