ObjectivesTo investigate the association between plasma N‐terminal pro‐atrial natriuretic peptide concentration and glomerular filtration rate in dogs.Materials and MethodsDogs were classified into four categories by bodyweight. Dogs were divided into four groups (Groups 1 to 4) based on glomerular filtration rate estimates using plasma iohexol clearance per bodyweight category. Generalised linear models were built to explore the relationship between plasma N‐terminal pro‐atrial natriuretic peptide concentration and glomerular filtration rate and the effect of confounders on plasma N‐terminal pro‐atrial natriuretic peptide concentration.ResultsFifty‐three dogs were included (Group 1, 25; Group 2, seven; Group 3, five; and Group 4, 16). The medians (interquartile range) N‐terminal pro‐atrial natriuretic peptide concentrations for Groups 1 to 4 were 7224 pg/mL (4766 to 10,254 mg/dL), 8958 pg/mL (4935 to 11,271 mg/dL), 9280 pg/mL (9195 to 10,384 mg/dL) and 12,683 pg/mL (9133 to 19,217 mg/dL), respectively. Group 4, estimated to have the highest reduction in glomerular filtration rate, had a higher plasma N‐terminal pro‐atrial natriuretic peptide concentration than Groups 1 to 3. Based on the final generalised linear model, influencing factors for plasma N‐terminal pro‐atrial natriuretic peptide concentration were plasma iohexol clearance (−0.136; 95% confidence interval, −0.227 to −0.046) and bodyweight (−0.058; 95% confidence interval, −0.098 to −0.018).Clinical SignificanceN‐terminal pro‐atrial natriuretic peptide concentration is associated with the glomerular filtration rate.