This paper presents results from a multi-participant project conducted by AOSTRA, ARC and industry to improve rod pumping efficiency for thermal and non-thermal oil fields in Alberta. It describes experimental and theoretical investigations on the hyrodynamics of rod pump valves that resulted in improved valve design and increased field production rates; and shows that, two of the most frequent problems encountered int he field are associated with sand and gas/steam inflow and may be alleviated through a better design of pump valves. These problems were examined in the laboratory (ARC) by testing ball-valve hydrodynamics at different GOR and inclination angles. Nineteen different valve designs were investigated using two laboratory facilities. Visual observations regarding critical GOR and inclination angles and quantitative measurements of pressure drop at different pump rates and fluid viscosity were obtained. A diagram, in which measured drag coefficient was plotted versus Reynolds number, was used to capture the steady and unsteady behaviours of the cage-ball systems. This diagram provided a basis for improving valve design. Following discussions of the laboratory findings with the project participants (field operators and manufactures), and at the instigation of one particular manufacturer, a new valve design (HIVAC) was compared manufactured and field tested at numerous sites. The field test results showed a significant increase in flow compared to conventional API values previously used at the same sites.