The aim was to compare the long-term outcomes of root canal treatment with that of follow-up-only in traumatized primary incisors in which dark discoloration is the only sign of injury. Root canal treatment was performed in 48 dark discolored asymptomatic primary incisors following trauma. Twenty-five of them [root canal treatment (RCT) group] were followed till eruption of their permanent successors. Ninety-seven dark discolored asymptomatic primary incisors were left untreated and invited for periodic clinical and radiographic examination. Of these, 28 [follow-up (FU) group] were followed till eruption of their permanent successors. The parameters examined included early extraction of the traumatized primary incisor, early or delayed eruption of the permanent successors, ectopic eruption of the permanent successor and signs of enamel hypopcalcification or hypoplasia in the permanent successor. Chi-square test was used for statistical analysis. Seven of 25 (28%) of the RCT group and 32% (nine of 28) of the FU group required early extraction. Five of 25 (20%) of the RCT group and 21% (six of 28) of the FU group showed early or delayed eruption of the permanent successors. Sixteen of 25 (64%) of the RCT group and 79% (22 of 28) of the FU group showed ectopic eruption of the permanent successors. Enamel hypopcalcification or hypoplasia in the permanent successors was equally found (36%) in both groups (nine of 25 in the RCT group and 10 of 28 in the FU group). None of differences was statistically significant. Root canal treatment of primary incisors that had change their color into a dark-gray hue following trauma with no other clinical or radiographic symptom is not necessary as it does not result in better outcomes in the primary teeth and their permanent successors.