Kerala, south western state of India is known for its abundant heavy mineral deposits along the coast. Beach placer deposits in Kerala is known for ilmenite, rutile, zircon, monazite, sillimanite and garnet. The grain size study of the sediments from Karamana river, flowing in the southern part of Kerala. Sediments from different parts of the river basin is studied, which enabled to understand the grain size variations with course of the river from the Peppara dam to Thiruvallam, very near to coast. Mineralogy of the river vary from one place to another depending different factors like host rocks in the province, climate conditions of the area, agents of transport and hydraulic condition during deposition, also can predict the actual source area associated with heavy mineral. Textural and heavy mineral studies of the placers of beach and Karamana river basins indicating the river is one of the important contributors of sediments to the western coast of the southern part of Kerala. Samples from various parts of the river indicate that the sediment is medium sand, moderately sorted, fine skewed and platykurtic. The characteristics of grain size distribution are related to the source rocks, process of weathering, and different sorting processes during transportation and deposition. The total heavy mineral percentage shows it is prominently enrichment in fine sand and very fine sands.