The great effectiveness of Acacia nilotica as a natural antitumor agent is well identified. However, the anticancer efficiency of fruit-part of A. nilotica against cervical and breast cancer cells, is still unknown. Hence, the present study for the first time, focuses on the dose and time related anticancer effects of A. nilotica fruit-extract, via its cytotoxic efficiency on HeLa and MCF7 cells. Furthermore, with the aim to check the anticancer tendency of A. nilotica-fruit-extract at molecular level, our study is the first-hand investigation that evaluates the expression of five crucial oncogenes (P53, PIK3CA, ERBB2, TNF and EGFR), in A. nilotica-treated HeLa and MCF7 cells, utilizing RT-qPCR. When HeLa and MCF7 cells were treated with increasing doses (3.25-100µl) of A. nilotica fruit-extract, for different time-durations (24, 48 and 72h). Dose-dependent effective cytotoxic effects of A. nilotica were noticed in treated-cancer cells. Based on time-durations, A. nilotica-induced cytotoxic effects was in highest rate on the time period of 24 h as compared to 48 and 72h. Furthermore, at this most effective time-period (24h), the low-dose (12.5µl) of A. nilotica was sufficient to show severe cytotoxic effects (27% and 26% cell-viability) on treated-cancer cells. In RT-qPCR analysis, the treatment of A. nilotica with its effective-dose (12.5µl) caused highly significant (p<0.01) decreased expressions for four (P53, PIK3CA, ERBB2 and EGFR) and three (P53, PIK3CA and ERBB2) oncogenes, in HeLa and MCF cells, respectively. This is the first-report on the low-dose effects of fruit-part of A. nilotica which can be effectively used to reduce cancer growth.