Introduction In 1954@ a group of users and manufacturers of sucker rod pumping equipment undertook a study in depth of the many complex problems associated with this means of lifting fluid from a well. To control and direct the effort@ Sucker Rod Pumping Research@ Incorporated@ a non-profit organization was created. The services of Midwest Research Institute at Kansas City were retained to perform the work necessary to achieve the objectives of the organization. The design calculations are based on correlations of the test data that were obtained during the research phase of the project. Sucker Rod Pumping Research@ Inc.@ before its dissolution@ released these correlated test results to the American Petroleum Institute for publication. This technical report for the design calculations of sucker rod pumping systems using conventional pumping units is based on these correlations. Three discussions included in the final reports of test results by Midwest Research Institute have been published for permanent reference in API Drilling and Production Practice (1968). These discussions include the following topics: vibration characteristics of sucker-rod strings; physical characteristics of sucker rods; dimensional analysis of sucker-rod pumping systems. A catalog of over 1100 dynamometer cards derived from the electronic analog computer for many combinations of the independent non-dimensional parameters Fo/Skr and N/No was included in the material released to API by Sucker Rod Pumping Research@ Inc. This catalog has been printed as API 11L2@ Catalog of Analog Computer Dynamometer Cards. Two computer programs have been developed from the data in API 11L. One program developed tabular material calculated for depths of 2000 ft to 12@000 ft in increments of 500 ft and for production rates of 100 barrels/day to over 1500 barrels/day in varying increments. Rod and pump size combinations as listed in Table 4.1 were used@ except for the elimination of rod no. 88 and rod no. 99. All API stroke lengths are covered. This material is printed as API 11L3@ Sucker Rod Pumping System Design Book. The other program developed a series of curves for selecting beam pumping units for depths of 1600 ft to 9900 ft and various rates of production and combinations of rod sizes@ pump sizes@ and speeds. Generally@ the limiting factor on the curve is the peak torque rating of the unit. This material was printed as API 11L4@ Curves for Selecting Beam Pumping Units (withdrawn from publication in 2008).