Effect of liquid organic humate fertilizer Humustim on chemical composition of aboveground biomass, root biomass and grain of spring forage pea was studied at the Institute of Forage Crops, Pleven, Bulgaria (2002–2004). Presowing treatment of seeds and treatments during vegetation were applied. The treatment with Humustim increased content of crude protein, macro elements and water–soluble carbohydrates in the aboveground biomass of plants. The highest content of crude protein (13.69%) and water–soluble carbohydrates (8.40%) was found for presowing treatment with Humustim at the dose of 1.2 L/t seeds + one treatment during vegetation. Applying of Humustim decreased crude protein content in roots from 5.0% to 17.8%. Treatment with Humustim had no effect on crude protein content in grain and increased water–soluble content (from 3.3% to 10.0%) and Са (from 11.1% to 77.8%). Better growth and development of spring forage pea were observed after treatment with Humustim–plant height and root length increased.