Effect of temperature on colostrometer readings for estimation of immunoglobulin concentration in bovine colostrum was investigated. Twenty-five colostrum samples were collected within 24 h postpartum from Holstein cows. Immunoglobulin concentration of colostrum was measured using a colostrometer through 5 degrees C increments from 0 to 40 degrees C. Two technicians measured independently a total of 225 samples. The agreement between technicians' readings was high (r = .98); thus, readings were averaged and used in regression analysis. A final regression model explained 92.5% of the total variation: corrected reading at 20 degrees C = uncorrected reading - 13.2 + .8 x temperature (degrees C). The regression equation was used to develop a conversion chart for practical field use.