Objective – The objective was to determine a technique for obtaining accurate rectal temperature measurements using commonly available digital thermometers. Design – The design tested the accuracy of rectal temperature measurements using commonly available digital thermometers intended for use in humans as well as the effect of insertion technique. Animals and Procedures – Students measured rectal temperature on sixteen crossbred cows on 53 separate occasions. Students' initial measurements were made with techniques acquired from their own previous experience. The students then repeated the temperature measurements after being instructed to insert the digital thermometer up to the display window. Rectal temperatures were also measured with a Cornell-style mercury thermometer completely inserted intra-rectally and allowed to incubate for two minutes. Accuracy of both types of thermometers, was determined by comparison with temperature measurements of a water bath using two calibrated traceable thermometers. The affect of three intra-rectal angles of insertion was also determined. Results - Rectal temperatures based on student initial temperature measurements, Cornell mercury thermometer, and digital thermometers inserted to the window were 38.46+/-0.07oC, 38.95 +/- 0.05 oC, 38.77 +/- 0.06 oC, respectively. Temperature readings were affected by 0.1 oC by angle of insertion. In a water bath, student-owned and traceable (reference) thermometers recorded temperatures that were not significantly different. Cornell mercury thermometers measured water bath temperatures that were 0.2 oC higher than that of calibrated thermometers. One of ten student digital thermometers was inaccurate. Conclusions and Clinical Relevance – Accurate temperature measurements can be obtained using digital thermometers if the thermometer is inserted to the display window. Angle of insertion of the digital thermometer is clinically unimportant and the thermometer's accuracy should be checked periodically.