Twenty‐five smoked and unsmoked fried bacon samples have been analysed by a group selective procedure to measure the concentration of apparent totalN‐nitroso compounds (ATNC). The levels of a range of individualN‐nitroso compounds, including simple volatileN‐nitrosamines,N‐nitrosothiazolidines,N‐nitrosoamino acids andN‐nitrosothiazolidine carboxylic acids have also been examined. Concentrations of ATNC varied from 430 to 6800μg(N‐NO)/kg with a mean of 2700μg(N‐NO)/kg. Protein‐boundN‐nitrosoproline was the most abundant compound detected in unsmoked bacon, mean 260μg/kg, and on average accounted for 4% of the ATNC concentration. For smoked bacon, boundN‐nitrosoproline was detected in levels of up to 890μg/kg and contributed 5% to the ATNC total. The most abundant compound present in smoked bacon wasN‐nitrosothiazolidine‐4‐carboxylic acid, mean 660μg/kg, and this accounted for 6% of the ATNC.N‐Nitrosothiazolidine, mean 340μg/kg, and 2‐(hydroxymethyl)‐3‐nitrosothiazolidine‐4‐carboxylic acid, mean 180μg/kg, were the next most prominent compounds detected in smoked bacon. The combined sum of all the individualN‐nitroso compounds measured accounted for, on average, 16% of the total ATNC. The identities of theN‐nitroso compounds comprising the majority of the ATNC in bacon remain unknown.