The Kufra and Sarir basins of Libya have huge ground-water resources. Three well fields-Sarir, Kufra, and Jalo-have been constructed for irrigation purposes. The Tazerbo and West Sarir well fields are under construction. Wells in these well fields have tapped only a small portion of the total ground water available. The hydrological behavior of the Sarir well field (determined by using analytical and numerical models) indicated a leaky artesian aquifer and a significant partial penetration effect. Long and short-term pump tests did not provide true estimates of the values of transmissivity and the coefficient of storage. A steady-state model of the Kufra and Sarir basins indicated a minimum of 80 m3 /s of underflow entering from Tibesti, Chad and Sudan. A transient model was constructed to pump a total of 120 m3 /s from 14 well fields. The simulation indicated that sufficient drawdown was available to last at least 50 years.