Microorganisms play an important role in providing nutrients for plants and also in soil development. Microorganisms help the release of nutrients from soil minerals using different mechanisms. This study was conducted to investigate the effects of two strains of Bacillus cereus on potassium and iron release from micaceous minerals under laboratory and rhizospheric conditions. Under laboratory condition, a completely randomized design with factorial arrangement with three replications consisting of two minerals (phlogopite and muscovite), two strains of bacteria (PTCC 1247 and PTCC 1665) and control (no bacteria) and eight time periods including 12 hours, 1, 2 , 4, 8, 16, 32 and 64 days were used. The micaceous minerals were affected by strains of bacteria for different time periods. Then, the amount of released potassium and iron (soluble) from minerals were measured by flame photometry and atomic absorption spectrometery, respectively. The greenhouse experiment was run using a completely randomized design with factorial arrangement and three replications. The treatments included four nutrient levels (complete, iron free, potassium free and iron and potassium free), two types of potassium bearing minerals (phlogopite and muscovite), two strains of bacteria (PTCC 1247 and PTCC 1665) and control. The pots were irrigated with four nutrient solutions during the growing season. After 150 days, shoot and root of plants were harvested, and the amount of potassium and iron was measured. Then, clay size particles were separated and clay mineral analysis was carried out by XRD. The results of the laboratory experiment showed that the rate of potassium and iron release dependson the type of mineral and bacterial strain. Strains PTCC 1665 released higher amount of potassium. Up to 32 days, potassium releaseincreased, but decreased afterward. At all the time periods, the released potassium was higher in PTCC 1665 than PTCC 1247 and control. However, unexpected results indicated that release of potassium from phlogopite was less than muscovite. Release of iron at the start of experiment (12h) increased, but decreased afterward and at the end of the experiment it increased again. After 12h, the highest amount of iron was released from phlogopite, and the amount of iron released from phlogopite was higher than muscovite. Results of greenhouse experiment showed that both strains of bacteria increased root and shoot dry weights. However, iron and potassium uptake increased under the treatment of bacteria strains in rhizosphere. Results of XRD analyses indicated that release of potassium and iron from interlayer and structure of phlogopite, respectively, led to hydroxyinterlayer vermiculate (HIV) formation. Whereas, no visible changes were observed in muscovite XRD patterns. The presence of bacteria in plant rhizosphere could release nutrients from soil minerals and lead to improve growth and yield of plants. In conclusion, the optimal use of useful type of bacteria could decrease chemical fertilizer application under greenhouse conditions.