Arsenic (As) poisoning in groundwater in Bihar (India) has caused various health related issues in the village population. In State of Bihar, India, it is estimated that more than 5 million people are drinking water with As concentrations greater than 10 μg L−1 (WHO permissible limit), and presently, the groundwater As contamination has been confirmed in 18 districts of the state of Bihar as per our study. The As contamination in the groundwater was maximum observed in Buxar district in the Simri village with maximum level of 1929 μg L−1. Apart from the symptoms of arsenicosis, the other symptoms observed were general body weakness, loss of appetite, anemia, cough or bronchitis, constipation, change in the mood or behavior, mental stress, hormonal imbalance etc. Our study has confirmed very high As contamination in the groundwater as well as in their biological samples of As exposed population. The present study deals with the evaluation of As contamination in groundwater and its correlation with incidences of cancer cases in As hit areas of Bihar. This will enable to make a strategic policy to control the cancer incidences in these areas with As contaminated aquifers.