In this updated review of tobacco smoking markers (smokers non-smokers) in various biological environments, during varied circumstances of use, we present the parameters known to be detectable to date. The focus is placed on:--certain bio-markers used in routine practice: plasmatic, urinary or salivary cotinine end-expired carbon monoxide,--certain minor tobacco alkaloids such as anabasine and anatabine, as potential bio-markers, particularly for monitoring abstinence during nicotinic substitution therapy,-- use of superficial body growths (hair and nails) as a biological environment for measuring nicotine and cotinine to monitor exposure to environmental tobacco smoke and fetal exposure.