Limited research has explored the accuracy of chemical dot thermometers for oral temperature measurement in adults. This study was undertaken to assess the agreement between oral temperatures taken with an electronic thermometer and single-use chemical dot thermometers in healthy women undergoing surgical delivery. During operative delivery, oral temperatures taken every 15 minutes with both the reference electronic thermometer (ETT) and a Tempa.DOT (TDT) chemical dot thermometer were compared. Data were analyzed using paired t tests, the Bland and Altman plot, and the concordance correlation coefficient. The total number of paired observations for the 62 subjects was 212. The mean difference between the two measurements was 0.35 +/- 0.32 degrees C (p < .0001, 95% CI 0.31, 0.40). Additional analysis indicated a serious undermeasurement by TDT of ETT temperatures. Data from multiple methods of analysis indicate that the Tempa.DOT chemical dot thermometer significantly undermeasures ETT and is not a reliable indicator of oral temperature.