Background : Circumcision is the removal of the prepuce that covers glands of penile and one of the most globally performed surgeries for therapeutic, prophylactic, religious, cultural and social reasons. In Indonesia the most frequent age is 5-18 years and the number of men who performed circumcision is 85% (8.7 million). In surgery process, patients are given anesthesia to avoid pain. Lidocaine 2% (7.0 mg/kg) is the commonly used anesthetic during circumcision. Many things can affect the onset of anesthetic drugs, such as pH of tissue, neurological morphology, lipid solubility, pKa of local anesthetic, and vasoconstrictor. Other factors, such as ease of diffusion through connective tissue, can affect onset of work in vivo. Sensitivity to blockade of calcium channels, potassium and N-methyl-D-aspartate receptor determined by anatomical factors. Hence, the correlation between penile length and onset of anesthesia block on circumcision surgery needs to be done. Methods : The design of this study is cross sectional and is used to analyze the correlation between penile length and onset of anesthesia block on circumcision surgery. The penile length and onset of anesthesia from fifteen participants of mass circumcision were measured. Sampling method used in this study was total sampling, so the entire population were samples. The data was then analyzed using Pearson Correlation Test. Result : The statistical correlation between penile length and onset of anesthesia block on circumcision surgery with Pearson correlation test showed p = 0.095 (not significant) where p> 0.05 and power of correlation (r) = 0.447 which show a moderate correlation Conclusion : This study shows that there is not significant relationship between penile length and onset of anesthesia block on circumcision surgery.