Chemically modified jute fibres are potentially useful as natural reinforcement in composite materials. Jute fibres were treated with 0.25%-1.0% sodium hydroxide (NaOH) solution for 0.5-48 h. The hydrophilicity, surface morphology, crystallinity index, thermal and mechanical characteristics of untreated and alkali treated fibres were studied. The two-parameter Weibull distribution model was applied to deal with the variation in mechanical properties of the natural fibres. Alkali treatment enhanced the tensile strength and elongation at break by 82% and 45%, respectively but decreased the hydrophilicity by 50.5% and the diameter of the fibres by 37%. (C) 2011 Elsevier Ltd. All rights reserved.