Soybean [Glycine max (L.) Merr.] seed quality in humid environments is related to the amount of water the mature seeds imbibe before harvest and during storage. The mechanism which restricts water uptake by the soybean seed has not been fully determined. The permeability of the seed coat to the passage of water vapor is presumed to be one such mechanism. The purpose of this study was to find genotypes which absorb water slowly and to identify factors associated with low water absorption.Twelve cultlvars, introductions and breeding lines, and seven progenies from different crosses were used to study the rate of water absorption at 100% relative humidity and 24 C for 8 days and under standard germinating conditions for 8 and 24 hours. Seed coats of selected samples of seed from the water absorption studies were observed using the scanning electron microscope.A negative correlation between seed size and the percentage of water uptake was found in some materials, but this relationship did not hold for all. A range of water uptake rates was observed. Furthermore, the shape and size of pores present in the seed coat were different for the various materials. Small seeds had a higher percentage by weight of seed coat and large, rounded pores, whereas large and medium seeds had a lower percentage of seed coat with smaller, elongated pores. Waxy material was embedded in different densities into the epidermis. Ecuador 2, Bragg, Ss‐Da‐010 and the progenies from Bragg ✕ (Cobb ✕ PI86490) F4 appear to imbibe water slowly. Small elongated pores and a high density of waxy material embedded in the epidermis were associated with low absorption.