A new cellulose-based tabletting excipient, hereinafter referred to as UICEL, has been developed by treating cellulose powder with an aqueous solution of sodium hydroxide (conc. ≥5N) and subsequently precipitating it with ethyl alcohol. UICEL is similar in structure to Avicel® PH-102, a commercial direct compression excipient commonly referred to as microcrystalline cellulose (MCC). It, however, shows the cellulose II lattice, while Avicel® PH-102 belongs to the cellulose I polymorphic form. As produced, UICEL consisted of a mixture of aggregated and non-aggregated fibers. The degrees of polymerization (DP) and crystallinity (DC) of UICEL, determined by the viscosity and powder X-ray methods, were 189–207 and 47–58%, respectively. Avicel® PH-102, by comparison, showed an aggregated structure with DP and DC values corresponding to 248 and 76.9%, respectively. Compared to Avicel® PH-102, UICEL shows higher true density, bulk density, tap density, Carr's index and Hausner ratio values. The mean deformation pressure ( P y) values calculated from the linear portion of the Heckel plots for UICEL and Avicel® PH-102 were about 104 and 87 MPa, respectively, suggesting that UICEL is less ductile than Avicel® PH-102. The hardness values of UICEL tablets increased nearly linearly with increasing compression pressures. Comparatively, Avicel® PH-102 formed stronger tablets. Irrespective of the compression pressure used, all UICEL tablets disintegrated within 15 s, whereas Avicel® PH-102 tablets of comparable strengths remained intact for over 12 h. In conclusion, the results show that UICEL can be used as a direct compression excipient, especially in the design and development of fast-disintegrating tablets.