Objectives: To evaluate and compare pain perception during administration of anaesthetic solution, effectiveness and preference between needle-less jet injector and conventional infiltration technique in children. Materials & Methods: Sixty-five patients with mean age of 8.33 years (SD 1.58, range 6-12) were anaesthetized by needle-less jet injector and conventional needle infiltration technique in two separate appointments for invasive/noninvasive dental procedures. Pain during administration and during treatment was evaluated by Likert and Wong Baker Faces Pain Rating scale. Patients gave their preference between two anaesthetic techniques for next course of treatment in third visit. Effectiveness of each anaesthetic technique was assessed by evaluating presence and absence of pain while probing gingivae, during use of high and low speed handpiece, during extraction and pulp extirpation. Results: Pain perception during administration of anaesthesia was significantly less by needle-less jet injector than conventional infiltration technique (P < 0.05) and there was no significant difference in effectiveness during treatment procedures (p ˃ 0.05). Postoperative complications viz. bleeding and bad taste during administration of anaesthetic solution was higher for jet injector (60% and 33.84% respectively) than conventional infiltration (21.53% & 12.31%). A total 81.5% of subjects preferred jet injectors over conventional infiltration technique. Conclusion: Needle-less jet injector was perceived to be significantly less painful and preferred means of anaesthetic drug administration over conventional needle infiltration. It provided adequate anaesthesia in maxillary and mandibular teeth during all the procedures, but it was less effective in mandibular molars for invasive procedures .Thus it is suggested that needle-less jet injector can be used as supplementary to conventional infiltration technique.