We investigate whether the fluctuations of agricultural output prices may explain the low level of input use in Sub-Saharan Africa. We combine data on local maize prices and data on farmers' fertilizer use over the 2009-2011 period in Burkina-Faso to estimate a panel-tobit model of fertilizer use. We separate the predictable and unpredictable components of maize price fluctuations and find that fertilizer use decreases when maize price fluctuations increase, and more specifically when unpredictable price fluctuations increase.