Natural wormholes and its astrophysical signatures have been suggested in various opportunities. By applying the strong field limit of gravitational lensing theory, we calculate the deflection angle and magnification curves produced by Morris-Thorne wormholes in asymptotically flat space-times. The results show that wormholes act like convergent lenses. Therefore, we show that it is hard to distinguish them from black holes using the deflection’s angle of the gravitational lens effect, in contrast with the results reported by Cramer et al. and Safanova et al.. However, we also show that it is possible, in principle, distinguish them by the magnification curves, in particular, by observing the position of the peak of the Einstein’s ring.