Pulsed-field-gradient (PFG) NMR methods provide a non-invasive technique for the observation of molecular translational diffusion. Magnetic susceptibility contrasts in heterogeneous samples cause the spins to experience rapidly varying fields as they diffuse. This results in an increased attenuation of the NMR signal and systematic errors in the measurement of diffusion. Here we present a new pulse sequence which combines the features of two well-known PFG sequences. The diffusion-sensitizing gradient pulse of the standard stimulated-echo PFG sequence is replaced by a series of gradient pulses of shorter duration and alternating sign. This new sequence eliminates the systematic errors caused by the inhomogeneous field and restores the signal level of the measurement. Experimental verification is provided.