Abstract: Mutational signatures offer insights into cancer etiology. Smoking tobacco is associated with three signatures involving single base substitutions (SBS4), double base substitutions (DBS2) and insertions/deletions (ID3). Combining mutational signatures with clinical data allows examination of temporal and quantitative aspects of carcinogenic exposures. We analyzed 132 non-small cell lung carcinoma (NSCLC) whole genomes, sequenced through the 100,000 Genomes Project (Genomics England), with paired clinical data available for 130/132 (98.5%). Clinical data included smoking status, duration, pack-years (py), and duration of smoking cessation. The majority were “ever-smokers” (ex-smokers: 90/130, 69.2%; current smokers: 32/130, 24.6%) and 120/122 (98.4%) had at least one smoking signature. DBS2 was the most sensitive signature for ever-smokers (118/122, 96.7%), although SBS4 was the optimal signature for diagnosing smoking-related NSCLCs (SBS4 positive likelihood ratio 7.15). An absence of ID3 best identified true never smoker NSCLCs (ID3 negative likelihood ratio 0.08). Ever-smokers had a higher tumor mutational burden (TMB) than never smokers (median 8.25 mutations/Mb vs 1.18 mutations/Mb