Arsenic is of concern as environmental pollutant because it is a ubiquitous element known to give rise to adverse human health effects ranging from minor disorders to cancer and acute death. Arsenic occurrence in the environment depends on such human activities as coal burning, use of pesticides, glass industry, electric application, veterinary medicine, etc. It has long been known that marine fishery products may contain high levels of arsenic. Fortunately, mainly in the organic, non-toxic form, with the average proportion of organic form in total arsenic between 71-79% and 50-97%. According to Lawrence et al., arsenic in marine fish was identified as arsenobetaine and, in shrimp only, arsenocholine. This paper examines the levels of total arsenic in the sample of the muscle and hepatopancreas of female and male Norway lobster, Nephrophs norvegicus L. from the area of Kvarneric Bay, Northeastern Adriatic (Croatia). The average values of arsenic in muscle from female and male lobster were 13.26 mg (kg and 14.20. mg/kg), respectively. In hepatopancreas the values were 17.12 mg/kg and 13.34 mg/kg for female and male, respectively. 11 refs., 1 fig., 1 tab.