The instrument registering sunshine duration was a Campbell-Stokes thermal heliograph placed at 20.7 m above ground level on top of the tower of the Meteorological Observatory of Maria Skłodowska-Curie University. The tower stands in Litewski Square in the centre of Lublin (geographical coordinates: φ = 51°14'54"N i λ = 22°33'38"E, h = 195.3 m above sea level). Due to the instrument's situations on the roof of the Observatory, the physical horizon did not significantly depart from the ideal one and did not obstruct sunshine registration. The paper contains a study of sunshine duration in Lublin during the years 1952-1991. The data analysed were registered by a Campbell-Stokes heliograph installed in the meteorological station of the Department of Meteorology and Climatology of the Maria Curie-Skłodowska University, situated in the centre of Lublin. The analysis considers the mean monthly, seasonal and annual values of sunshine duration, the number of days without sunshine and days with sunshine duration ≥ 4, 6 or 10 h. The mean annual sunshine duration in Lublin amounts to 1542 h (average daily sunshine duration reached 4.2 h) which corresponds to 34.4% of possible sunshine duration. It is 16 h more in comparison with the mean value for Poland for the period of 1951-1975. The yearly sums of sunshine durations were different and they changed within the range 1219.7 h in 1980 to 1966.0 h in 1953. The mean number of days without sunshine amounts to 94 and it changed within the range from 64 (in 1955) to 122 (in 1970). The monthly sums of sunshine duration in Lublin are similar to the mean values for Poland given by Kuczmarski. In August and October the Sun shines 8 h longer in Lublin than an average in Poland, however in March and September its duration is 5 h shorter. The positive as well as negative deviation of the sunshine duration, compared with the mean values for Poland, are statistically significant and occur at the significance level of α = 0.01.