Objective To compare the effectiveness of anatomical single-bundle (ASB) and over-the-top singlebundle (OSB) reconstruction of the anterior cruciate l igament (ACL). Methods Between January 2008 and June 2008, 64 patients with ACL injury underwent arthroscopic ACL reconstruction. ASB ACL reconstruction was performed in 28 cases (ASB group) and OSB ACL reconstruction in 36 cases (OSB group). There was no significant difference in gender, age, diseaseduration, International Knee Documentation Committee (IKDC) score, Lysholm score, and side-to-side difference between 2 groups (P gt; 0.05). Results All incisions healed by first intention; no infection or other compl ications occurred. All cases were followed up 20-24 months (mean, 21.5 months). There were significant differences in the IKDC score, Lysholm score, and the side-to-side difference between last follow-up and preoperation in 2 groups (P lt; 0.05), but there was no significant difference between 2 groups at last follow-up (P gt; 0.05). Significant differences were found in negative rate of the pivot shift test between last follow-up and preoperation in ASB group and between 2 groups at last follow-up (P lt; 0.05), but there was no significant difference between last follow-up and preoperation in OSB group (P gt; 0.05). Conclusion The effectiveness of arthroscopic ASB ACL reconstruction is better than that of arthroscopic OSB ACL reconstruction, especially in controll ing rotational stabil ity.