This paper uses household survey data from Benin to evaluate how grain quality affects maize prices in rural markets of sub-Saharan Africa. Stated preference methods reveal that a 10% increase in insect damage results in a 9% maize price discount. However, revealed preference results from farmers involved in past market transactions indicate that this discount is only 3 %. Evidence also suggests that this discount is larger in periods of maize abundance than in the lean periods when maize is scarce. Our results contribute to explain why many smallholder farmers sell maize at harvest and do not invest in storage technology that would improve grain quality later in the season.