Isotropically　consolidated　undrained　triaxial　compression　shear　tests　were　performed　on　three　reconstituted　clays　to　investigate　the　effect　of　initial　water　content　w0　on　undrained　strength　behaviour.　The　values　of　w0　were　adjusted　within　the　range　of　10-20　times　the　liquid　limit.　The　predominant　clay　mineral　is　identified　as　illite　for　the　considered　clays,　based　on　a　semi-quantitative　analysis　of　the　X-ray　diffraction　patterns.　The　laboratory　tests　show　that　the　stress-strain　curve　in　terms　of　deviator　stress　against　axial　strain　and　the　effective　stress　path　in　terms　of　deviator　stress　against　effective　mean　stress　are　significantly　affected　by　w0.　The　undrained　strength　ratio　R*su,　defined　as　the　ratio　of　the　undrained　shear　strength　S*u　to　the　isotropic　consolidation　stress,　varies　with　w0　within　a　wide　spectrum,　ranging　from　0.　28　to　0.　60　for　the　three　reconstituted　clays　investigated.　The　relationship　between　void　index　Iv　and　S*u　changes　with　R*su,　and　becomes　identical　to　the　intrinsic　strength　line　proposed　by　Chandler　when　R*su　=　0.33.　It　is　also　evidenced　from　the　laboratory　tests　that　the　value　of　S*u　depends　on　both　the　water　content　and　the　liquid　limit.　©　2013　Thomas　Telford　Ltd.