Therefore, an experiment was undertaken to determine the suitable planting spaces (40, 50 and 60 cm) of Melissa officinalis L., plant and the best treatment of nitrogen, phosphate and potassium biofertilizers treatments plus half dosage of the full recommended dose of NPK mineral fertilizer. Results showed that planting spaces recorded various different effects on growth characters. The narrow space (40 cm) resulted in the tallest plants, the highest Leaves and essential oil yield per fed, while the wider space (60 cm) produced the heaviest leaves dry weight per plant, the highest number of branches, essential oil percentage, total chlorophyll content as well as N, P, K and total carbohydrates percentages. The most growth characters and yield as well as chemical composition improved and increased when soil was inoculated by a different inoculums of nitrogen-fixing bacteria (nitrobein), Bacillus polymyxa as a phosphate dissolving bacteria (phosphorein), and foliar spray of potassium as a (potassein-p) were used in combination with half of the full recommended dose of NPK mineral fertilizer compared with the control treatment received only the full recommended dose of NPK mineral fertilizer. Moreover, the interaction treatments indicated that the highest means values for most growth characters, active constituents and chemical composition were recorded at 40 cm plant space with biofertilizers treatment (nitrobein + phosphorein + potasei-p) as a mixture plus half of the recommended dose of NPK mineral fertilizer. Gas chromatography analysis of essential oil indicated that the main components were citral and geranial. The components were positively affected by different combined treatments between planting space and biofertilization. So, cultivated lemon balm plants at 40cm planting space and applying 50 % of the recommended dose of NPK plus mixture of biofertizers can save half of the quantity of mineral fertilizer decreases the production cost and environmental pollution as well as gives high quality product.