Abstract: Critical investigation were carried out to study the effect of silica fume on the compressive strength of cementitious grouts. The silica fume was added in different percentages of total mix, the percentages were 2%, 3.5%, 5%,6. 5%, and 8%. Cement component in the grout mix was varied between 30% to 50%, 13% water and 0.7% Salphonated naphthalene-formaldehyde condensate (SNF) were added in all mixes. Cemetitious material like plaster of paris and aluminium powder were also added in fixed percentages of 3% and 0.005%. Total number of mixes studied was 25. Increase in cement component is found to have increased the compressive strength, however the addition of silica fume in different proportions have contributed to compressive strength development. It is observed that 2% of silica fume and 3.5% of silica fume has resulted in better compressive strengths. The results obtained are critically analysed and are presented and discussed in this paper.