Gum arabic has a wide range of industrial uses worldwide and is collected in sparsely populated dry land regions typically inhabited by poor households. In the study sample of 201 households in northern Kenya, observed marketed quantities were low. Primary data collected through personal interviews were complemented by GIS data on precipitation and vegetation cover. An economic model was developed in which a shortage of rainfall decreases the return to alternative sources of income by more than the return to gum collection, which point to an increasing relative return to gum collection, thus explaining why rainfall shortage can have a positive effect on marketed quantities. Regression results confirm this prediction. We conclude that gum arabic collection is an activity with low economic returns yet provides a safety net when other sources of income fall short.