We consider slow standing waves that are impulsively excited in a curved solar coronal loop. The numerical model we implement includes the effect of nonlinearity in the frame of two-dimensional ideal magnetohydro-dynamics. We discuss the role of curved magnetic field lines and of the slow and fast pulses overlapping at one of the loop's footpoints in the excitation and attenuation of slow standing waves. We find that slow waves can be excited faster in curved loops than in slabs due to the combined effect of the pulse inside and outside the loop. © 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A.