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Phytolith studies were carried out on a 7.8 m profile of mid-late Holocene succession located at Itola, Dhadhar river basin that lies in the sub-humid belt bordering the serni-arid zone of western India. The exposed sedi-, ment succession consists of alternating sand, silt and clay with thin layers of terrigenous charcoal partings dated to 3960 +/- 510 cal yrs BP and pottery pieces. at the basal-most part. Since grasses respond readily to precipitation, the ratio of characteristic cool and moist to warm and humid phytolith associations was used to reconstruct the mid-late Holocene monsoonal variability in this region. The study indicates weakning of the SW monsoon during mid-late Holocene. Winter precipitation, known to have commenced during early-mid Holocene, was still persistent around 3960 cal yrs BP, leading to cool and moist climatic conditions. Following a brief phase of dry climatic conditions, winter precipitation. also gradually died out resulting in a dry climate. The SW monsoon regained its strength during the later part of late Holocene. The presence of vast archeological sites of the Indus Valley Civilization in Gujarat region during mid Holocene and their subsequent decline from this region during late Holocene raises questions regarding its relationship with the monsoonal variability during that time-span. The phytolith studies of a late Holocene sequence in mainland Gujarat has provided evidence of extremely weak winter as well as SW monsoonal activity resulting into dry climatic conditions during mid Holocene, a possible cause in the decline of the Indus Valley Civilization.