To examine the labelling status of trans-fat of pre-packaged foods sold in Hong Kong. Data from 19 027 items in the 2019 FoodSwitch Hong Kong database were used. Ingredient lists were screened to identify specific (e.g. partially hydrogenated vegetable oil, PHVO) and non-specific trans-fat ingredient indicators (e.g. hydrogenated oil). Trans-fat content was obtained from the on-pack nutrition labels, which was converted into proportion of total fat (%total fat). Descriptive statistics were calculated for trans-fat content and the number of specific, non-specific and total trans-fat ingredients indicators found on the ingredients lists. Comparisons were made between regions using one-way ANOVA and χ2 for continuous and categorical variables, respectively. Cross-sectional audit. Not applicable. A total of 729 items (3·8 % of all products) reported to contain industrially produced trans-fat, with a median of 0·4 g/100 g or 100 ml (interquartile range (IQR): 0·1-0·6) and 1·2 %totalfat (IQR: 0·6-2·9). 'Bread and bakery products' had the highest proportion of items with industrially produced trans-fat (18·9 %). 'Non-alcoholic beverages' had the highest proportion of products of 'false negatives' labelling (e.g. labelled as 0 trans-fat but contains PHVO; 59·3 %). The majority of products with trans-fat indicator originated from Asia (70 %). According to the labelling ∼4 % of pre-packaged food and beverages sold in Hong Kong in 2019 contained industrially produced trans-fat, and a third of these had trans-fat >2 %total fat. The ambiguous trans-fat labelling in Hong Kong may not effectively assist consumers in identifying products free from industrially produced trans-fat.