Abstract Aim This was to investigate the root canal morphology of primary molar teeth using micro-computed tomography. Methods Primary maxillary (n=20) and mandibular (n=20) molars were scanned and analysed regarding the number, location, volume, area, structured model index (SMI), area, roundness, diameters, and length of canals, as well as the thickness of dentine in the apical third. Data were statistically compared by using paired-samplet test, independent sample t test, and one-way analysis of variance with significance level set as 5 %. Results Overall, no statistical differences were found between the canals with respect to length, SMI, dentine thickness, area, roundness, and diameter (p<0.05). A double canal system was observed in the mesial and mesio-buccal roots of the mandibular and maxillary molars, respectively. The thickness in the internal aspect of the roots was lower than in the external aspect. Cross-sectional evaluation of the roots in the a...