Engineering design is naturally dominated by technological knowledge, but there is a need now for greater consideration to be taken of the needs of individual humans and of society in general. Many of the criticisms of engineering designs (civil, mechanical, electrical and chemical) made during the last twenty years, could have been avoided if more consideration had been taken of the human factors. In the processing and manufacturing industries concerned with marketing consumer products, there has developed a process for design which combines the technological design with consumer needs - this is called product development. Product development is the process used from the development of the initial idea for a new product to the final launching of the product on the market. At all stages of product development, the consumer is involved in the design of the product from the initial creation of the product idea to the testing of the final product. The human needs from a product and the methods used to incorporate them in the design are discussed. It is suggested that these methods can be used to incorporate the human factor into any engineering design, and that the product development process can be applied in other areas of engineering as well as the consumer product industries.