This paper presents a methodology for risk analysis of seasonal agricultural drought on low Pacific islands. Results are presented for a pilot study of low islands in the Cook Islands group. Drought is defined in terms of the number of consecutive days during which the actual evapotranspiration to potential evapotranspiration ratio (AE/PE) remains below a threshold value. A water balance model is used to estimate the AE/PE time series. Drought hazard is determined on the basis of the AE/PE time series as the return period of a particular drought magnitude ( AE/PE threshold) and duration (number of consecutive days below AE/PE threshold). Drought hazard is determined for each of six two-month seasons. This study provides a method of quantitative drought hazard assessment for application in agricultural development planning.