Purpose : To compare the changes of the patellar height, patellofemoral alignment and subjective symptom and to compare the effects of patellar tendon harvest after anterior cruciate ligament(ACL) reconstruction using autograft and allograft. Materials and Method : ACL reconstruction was performed on 87 patients who were followed up for minimum 1 year. The group I was 52 patients who were operated with bone-patellar tendon-bone autograft and the group II was 35 patients who were operated with bone-patellar tendon-bone allograft and achilles tendon allograft. At the time of follow-up, the authors evaluated the patellar height by Blackburne-Peel method, Merchant congruence angle, Lateral patellofemoral angle and subjective symptoms were assessed. Results : The patellar heights were significantly decreased from 0.86 preoperatively to 0.80 postoperatively in the group I and from 0.87 preoperatively to 0.83 postoperatively in the group II. There were no significant differences in the lateral patellofemoral angles between the both groups but in the Merchant congruence angle, significant differences were observed in the both groups, from$-1.43^{circ}$ preoperatively to-$5.43^{circ}$ postoperalively in the group I and from$-1.53^{circ}$ preoperatively to$-3.65^{circ}$ postoperatively in the group II. Conclusion : After ACL reconstruction, the patellofemoral alignment was changed and this kind of changes may be caused by multiple factorials such as harvest of autografts, ACL reconstruction itself, and quadriceps muscle atrophy.