Most inoculation studies failed to improve crops production. This was attributed to inefficiency of bacteria used without interest with other factors. Moreover these studies concentrate in nitrogen uptake only and ignore other important minerals. Therefore this study was conducted to investigate the effect of soil type and KNO 3 on nodulation of groundnut inoculated with fast growing bacteria isolated from groundnut and to test the ability of the isolates to enhance groundnut uptake of nitrogen and some minerals. In this study three bacterial strains were isolated from El-Gadarif, El-Gezira and El-Obied soils and one reference strain (TAL169) were tested in tubes and pots experiments. Nitrogen and minerals content were estimated by Kjeldhal and spectrophotometers method, respectively. Nodule formation was completely inhibited in groundnut when KNO 3 was added to the different soils. Among the different soils tested El-Obied soil was the best in response to inoculation with the different strains and KNO 3 while El-Gezira soil was the least. The strain isolated from El-Gadarif soil was the best in promoting groundnut growth and increasing nitrogen content in all soils. The nitrogen content was 3.13% in its soil and 2.88 and 2.50% in El-Obied and El-Gezira soils, respectively. Inoculation with the different strains was found to improve Mg uptake only among the tested minerals. The study concluded that there is variation in response of the different soils to inoculation with different strains. So background about soil type, properties and its nitrate content will lead to successful inoculation which will increase crop production.