We consider the class of four-dimensional N = 2 gauged supergravities whose maximally symmetric ground states leave only one of the two supersymmetries intact. For these theories we derive the low-energy effective action below the scale of partial supersymmetry breaking and compute the N = 1 couplings in terms of the N = 2 `input data'. We show that this effective action satisfies the constraints of N = 1 supergravity in that its s-model metric is Kahler, while the superpotential and the gauge kinetic functions are holomorphic. As an example we discuss the N = 1 effective supergravity of type II compactifications.