A time series of mean-sea-level atmospheric pressure was built from observations performed in Trieste from 1 January 1841 to 31 December 2018. Data until 1877 come from direct measurements with mercury barometers, from 1878 onwards barograph records are also available. The main time series consists of mean daily values, computed from 24 hourly data, when possible, or otherwise adjusted to 24-hr means. The time series was homogenized on the basis of the available metadata, reducing pressure to 0° C and to mean sea level. Monthly and annual means were also computed from the daily values.