In order to evaluate the of vermicompost, plant growth promoting rhizobacteria and humic acid on growth factores of Mentha piperita L., an experiment was conducted in 2010 at Farm of Islamic Azad University-Arak Branch in central province. Experiment was factorial based on randomized complete block design with three replications. Treatments were plant growth promoting rhizobacteria (b0=non-inoculated and b1=inoculated), vermicompost (v0=0, v1=5 Ton/ ha) and humic acid (h0= without spray and h1=spray). Characters such as plant height, leaf dry weight, shoot dry weight, leaf area, yield of fresh matter, yield of dry matter were measured. Results showed that the use of vermicompost, plant growth promoting rhizobacteria and humic acid on the growth of Mentha peperita were significant at the 1% level. Among the treatments tested, the treatments of all three factors combined (b1v1h1 )with 47.73 cm height, 36.93 g dry weight of leaf, 67.30 g dry weight per plant, 1676.5 cm2 leaf area, 18 588 kg yield of fresh mater, 3879.2 kg yield of dry matter had significantly different with the control treatment.