The aim of this study was to prepare sustained release suppositories containing metoclopramide HCl, an antiemetic drug for rectal administration. The effect of the water swellable polymer, hydroxylpropylmethyl cellulose (HPMC) and the anionic polymer, xanthan gum on In vitro release of metoclopramide HCl from suppositories was studied. Metoclopramide HCl sustained release suppositories were formulated with the different ratios of release modifier by fusion method. A combination of 1:3 PEG400: PEG4000 was used as hydrophilic suppository base. Weight variation, drug content, hardness (fracture point), disintegration time, friability, melting time and In vitro release experiments were conducted on the prepared formulations. The results indicated that HPMC could sustain drug release more effectively than xanthan gum. Least metoclopramide HCl release rate was shown by suppositories containing 20% HPMC (F7). However, the results of investigation clearly suggest that sustained release suppositories containing 10% HPMC (F6) or 20% xanthan gum (F4) were found more suitable for rectal drug delivery system of metoclopramide HCl and can be successfully designed to achieve suitable sustained delivery of metoclopramide HCl for particular clinical conditions. F4 and F6 showed non-Fickian mechanism and zero order kinetics.