The main objective of this study was to study solely early postoperative morbidity following anterior cruciate ligament (ACL) reconstruction by comparing the gold standard procedure, the bone‐patellar tendon‐bone graft (BTB), and one of the most common alternatives, the semitendinosus tendon graft (ST). The prospective study included 107 randomized patients (50 BTB and 57 ST). The follow‐up period was set to 20–35 weeks postoperatively (mean 26.8±3.5 weeks). One patient suffered early graft rupture and 89 (84%) of the remaining 106 patients were able to attend the follow‐up within the given time limit. There were no differences in sick leave between the groups. The Lysholm score, Tegner activity level score and Visual Analog Scales (VAS) with the questions “How does your knee function?” and “How does your knee affect your activity level?” revealed no differences between the groups. Subjective patellofemoral pain, patellofemoral compartment findings and donor site morbidity were more common in the BTB group, P<0.05. Lachman test grade 1+ was more common in the ST group, P<0.05, but there was no significant difference in instrumented Lachman side‐to‐side comparison. The ST group scored better in the one‐leg hop test than the BTB group, P<0.05. No correlations between these clinical and functional findings and subjective knee function scores were found. In conclusion, ACL reconstruction with ST tendon graft presented fewer short‐term postoperative problems as compared to reconstruction with BTB.