The hydrocyclone is considered one of the most important industrial separators. It has been used for more than 100 years due to its simple design, low cost, easy operation, and low maintenance. One of the most important areas of application of hydrocyclone in industry is the separation of solids from liquid. A cyclone used for this duty is usually referred to as a cyclone thickener. Under the general heading of the separation of solids from liquid; two extreme cases can be recognised. These are "thickening" and "clarification". A hydrocyclone as a single unit can not be used for this purpose efficiently. Accordingly, the concept of the three-product cyclone is developed from the need to have a cyclone which can be used efficiently in the separation of solid from liquid applications. In an attempt to put this concept into effect, a new design of three-product hydrocyclone has been developed to generate a third product in which the middling particles should be collected for further treatment. In this paper, the design and operation of the three-product hydrocyclone are described. The influence of some parameters such as vortex finder diameter, middling opening diameter, and apex diameter on the solid percent recovered in the three products is investigated. The obtained results showed that the new three-product hydrocyclone has the ability to produce efficiently three different products according to their solids percent, water percent and particle size distributions.