PURPOSE: To evaluate the tableting properties of microcrystalline starch (MCS) used as a direct compression excipient in the formulation of ascorbic acid tablets and to compare with the properties of tablets produced using microcrystalline cellulose (MCC). METHODS: MCS was obtained by partial hydrolysis of cassava (Manihot esculenta Crantz) starch using the enzyme, á-amylase. The hydrolysis was allowed to proceed for 5 hr under controlled temperature and pH (56 °C, 6). The derived MCS was recovered by filtration after precipitation with ethanol (95%v/v). Powder properties were investigated and tablets of ascorbic acid were formulated using MCS and MCC as direct compression excipients. RESULTS: Mechanical properties of tablets formulated with MCS were comparable to those of MCC. Tablets formulated with MCS disintegrated within 15 min and gave a 100% release of ascorbic acid within 30 min compared to MCC which disintegrated after 60 min. CONCLUSION: MCS can be incorporated as a direct compression excipient in the formulation of heat and/or moisture sensitive drugs by direct compression.