Abstract: In order to investigate the releases of aldehydes and ketones in mainstream smoke of cigarettes of different sizes, a gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for simultaneous determining 95 aldehyde and ketone components in mainstream cigarette smoke. The samples of slim, medium and king-sized cigarettes were prepared with the same tobacco blend. Eight irritants with lower molecular weights and 95 aroma components of aldehydes and ketones were measured. One-way analysis of variance (ANOVA) was used to screen the different compounds. The results showed that: 1) The calibration curves of all the aroma components presented good linearity (R²>0.99). The intra- and inter-day relative standard deviations (RSDs) were in the ranges of 1.4%-11.1% and 0.7%-24.3% respectively, wherein the RSDs of 70 compounds were less than 10%. The recoveries of 92 compounds ranged from 70% to 120% at three spiked levels. 2) A total of 68 different compounds were measured. The releases per unit tar for seven irritant components (except formaldehyde) with lower molecular weights from the king-sized cigarettes were higher than those from the medium and slim cigarettes. 3) For aldehydes and ketones with boiling points ≤133 ℃, such as 2-hexanone, acetaldehyde, and 2, 3-pentandione, their releases were higher from the king-sized cigarettes than those from the medium and slim cigarettes. For aldehydes and ketones (except 3-methylacetophenone and cinnamaldehyde) with boiling points ≥215 ℃, such as 2-hydroxy-3-methyl-2-cyclopentene-1-one, vanillin and 5-hydroxymethylfurfural, their releases were significantly lower from the king-sized cigarettes than those from the medium and slime cigarettes. For aldehydes and ketones (except 2-heptanone, 2-methyloxolan-3-one and 6-methyl-3, 5-heptadien-2-one) with boiling points ranged from 133 to 215 ℃, such as 2-cyclopentene-1-one, 2-methyl-2- cyclopentene-1-one and furfural, their releases were higher from the medium cigarettes than those from the slim and king-sized cigarettes.