In developing countries like Ethiopia construction is a very wide industry. Almost all constructions in Ethiopia involve production and use of concrete. Concrete being one of the important constituents of many of the construction projects, in addition to its subjectivity to variability, requires a close and thorough care and handling in construction projects. The constituents of concrete, which majority of them occur naturally, are subjected to a wide range of variability and quality problems. Therefore, with this respect a research was carried out to assess and investigate the effect of quality problems of fine aggregate on concrete quality. The purpose of this study was to find out the effect of silt and clay in sand on concrete workability and compressive strength. A further subsidiary aim was to explore construction sites in Bahir Dar to find out their awareness on impurities in sand and their effect on concrete workability and compressive strength. Therefore, to achieve the research objective, sand samples for laboratory investigation were collected based on study area assessment results. Sample construction projects were assessed and their awareness on the effect of sand quality specifically on silt and clay content in sand was identified. Laboratory tests were carried out to strengthen the research and to show the effect of silt and clay content in sand on specifically workability and compressive strength of concrete. The research findings show that the fine aggregate in and around Bahir Dar contains high amount of silt and clay content in it. In addition, the awareness of the people in the construction industry on the effect of those silt and clays in sand is poor. The way this sand is extracted from the source, loaded to vehicles, transported to site and stored in site all contribute in introducing impurities within the sand. The laboratory results show that workability of concrete decreases with an increase in silt and clay content in sand. In addition to that, a concrete produced with sand that contains a silt and clay content greater than 0.24% will fail to achieve the target mean strength.