Purpose: To compare the effectiveness of articaine local infiltration with lidocaine inferior alveolar nerve block (IANB) for restorative treat- ment of primary mandibular molars (PMMs). Methods: In this double-blind, parallel-design, randomized, controlled, clinical trial, participants were enrolled according to specified inclusion criteria (four to 10 years of age, need of PMM restorations, Frankel four behavior) and randomly assigned into either an articaine or lidocaine group. One investigator administrated all local anesthesia (LA). Nineteen trained and calibrated exam- iners, blinded to LA type, evaluated participants' reactions during LA administration and treatment using Modified Behavioral Pain Scale (MBPS). Participants rated their experiences using Wong-Baker FACES Pain Rating Scale (WBFS). The subjects' blood pressure and pulse were recorded throughout procedures. Statistical analysis employed Mann Whitney-U test, repeated measures analysis of variance (P<0.05), and Cohen's kappa. Results: A total of 110 participants (n equals 55 per group; mean age equals 6.42 years; 60 percent males) were enrolled. The mean MBPS rating during LA administration was higher for lidocaine IANB (3.89) compared to articaine infiltration (2.24; P<0.001). The mean MBPS rating through- out treatment was higher for the lidocaine group (2.51) compared to articaine group (1.69; P=0.012). The lidocaine group had a mean WBFS score of 1.64, while for the articaine group WBFS was 0.872 (P=0.089). All physiological measurements were within normal limits with no difference between groups. Conclusions: This study demonstrated that local infiltration with articaine was less distressing upon administration and may be considered safe and effective alternative to lidocaine IANB for restorative treatment in PMMs.