Abstract: The present invention relates to composition of metalworking fluid based on heavy alkyl benzenes having 20 to 22 alkyl carbon atoms and process for the preparation thereof. The heavy alkyl benzene based, less toxic, soluble metalworking fluid composition comprises heavy alkyl benzene, emulsifier, lubricity booster, antioxidant, fungicide, extreme pressure additive, antirust, co-surfactant, coupling agent and alkali component. The process comprises tailoring the heavy alkyl benzene, removing of insoluble matter from the heavy alkylate, addition of emulsifier, additives, coupling agent and co-surfactant, homogenizing the mixture at 20-120° C., followed by conditioning of the soluble metal working fluid concentrate which can be used as emulsion in water.