[1] A simple technique is introduced to control hydraulic fractures in laboratory samples. This is achieved by heating or cooling samples prior to injecting the fracturing liquid, so that the induced thermal stresses govern the fracture orientation. We developed a simple theoretical model to parameterize experiments in laboratory settings and for materials that are different from ours. We also illustrate the utility of the technique with two examples: (1) mixed mode I + III hydraulic fracture propagation and (2) visualization of the fluid flow in the created fracture. In some cases, a similar technique may also be applicable for controlling the orientation of hydraulic fractures in field conditions.