Seed spacing uniformity is one of the important criteria in determining the planting performance of precision planters. The development of various measurement methods with different advantages has been ongoing for years to determine seed spacing. The objective of this study was to develop an opto-electronic measurement system for use in the measurement of seed spacing during the laboratory tests of precision planters and to examine the success of the system. The success of the developed system was tested by comparing the measurements on the sticky belt using 10 different seeds with different physical properties. The R-2, MAPE, e(i), beta(0) nu e beta(1) values for all seeds were determined respectively as 0.998, 3.60%, 0.484 cm, 0.022 and 1.012 as a result of the trials carried out. The system yielded very fast and correct results and there was no need for complex calibration and adjustment procedures. The opto-electronic measurement system can be used to measure seed spacing in laboratory tests for precision planters. (C) 2017 Elsevier Ltd. All rights reserved.