Diagnosis of arsenicosis relies on both clinical and laboratory criteria, but principally it can be diagnosed on the basis of its cutaneous manifestations. Cutaneous manifestations (melanosis, keratosis, and cutaneous cancers) are essential clues in the diagnosis, and trained dermatologists or arsenic experts are able to clinically confirm a case even without laboratory backup. Although systemic manifestations are not considered as diagnostic hallmarks, yet their presence serves as important telltale signs in arriving at the diagnosis. In countries where laboratory facilities are available, measuring the level of arsenic in drinking water (consumed in the last 6 months), urine, hair, and nails is of immense value. Newer biomarkers of arsenic exposure are being explored to provide early information about arsenic intoxication, of which urinary porphyrin level, blood metallothionein have shown promising results. Controlling the problem of arsenicosis depends on various factors, of which the most important is cessation of intake of arsenic-contaminated water. Deep wells, traditional dug wells, treatment of surface water, rainwater harvesting, and removing arsenic from the contaminated water by arsenic removal plant or arsenic treatment unit are the available options for providing arsenic-free drinking water. The role of nutrition and antioxidants in preventing the onset of symptoms of arsenicosis is also of importance. Nonspecific therapies (e.g., keratolytics for hyperkeratosis) cannot also be ignored and serve as palliative measures. The persons affected need to be followed up at regular intervals to detect the onset of cancers (if any) at the earliest. Role of counseling and education should never be underestimated since absence of public awareness can undermine all efforts of mitigation measures.