Our paper deals with mercury accumulation in Norway spruce needles (Picea abies (L.) Karst.) with regard to needle age. Samples of spruce branches from Slovakia were separated according to age. There were 85 samples of 1-yr-old needles, 85 samples of 2-yr-old ones, 82 and 61 samples of 3- and 4-year-old needles, respectively. Dried needles were homogenized by means of a ball mill. Mercury was determined by the Advanced Mercury Analyser AMA 254 (a single-purpose absorption spectrophotometer). The average concentration was 0.041 mg·kg^-1, 0.048 mg·kg^-1, 0.064 mg·kg^-1, and 0.068 mg·kg^-1 in dry matter of 1-, 2-, 3-, and 4-year-old needles, respectively. The variance analysis of mercury concentration in individual age classes shows statistically significant differences between average values on a 5% level of importance. The follow-up Duncan’s test showed that there were significant differences between average values of non-adjacent age classes (first ↔ third and fourth; second ↔ fourth) of needles. The acquired data points out the falling tendency of mercury concentrations in Norway spruce needles as a reflection of improving environmental conditions.