As an extension of orthogonal matching pursuit (OMP) for improving the recovery performance of sparse signals, generalized OMP (gOMP) has recently been studied in the literature. In this paper, we present a new analysis of the gOMP algorithm using the restricted isometry property (RIP). We show that if a measurement matrix Φ ∈ Rm×n satisfies the RIP with isometry constant δmax{9,S+1}K ≤ 1 8 , then gOMP performs stable reconstruction of all K-sparse signals x ∈ Rn from the noisy measurements y = Φx + v, within max K, 8K S iterations, where v is the noise vector and S is the number of indices chosen in each iteration of the gOMP algorithm. For Gaussian random measurements, our result indicates that the number of required measurements is essentially m = O(K log n K ), which is a significant improvement over the existing result m = O(K2 log n K ), especially for large K.