The Greenland smoothcockle (Serripes groenlandicus) has a circumpolar distribution in the northern hemisphere. Despite such a wide range and potential commercial importance, little is known about most aspects of the biology of this species. As part of studying the growth rate of this cockle species, we compared 3 methods that could be used to estimate the age of S. groenlandicus: (1) reading the external rings on the shell, (2) counting the growth rings on thin sections of the chondrophore, and (3) counting growth rings of whole shell sections. The chondrophore proved to be the best region to count the growth bands compared with the other regions in the cockle shell. Age bias plots and the coefficient of variation indicated that our ageing method represents a nonbiased and precise approach. This age method was validated by using Marginal increments Ratio method (MIR) to confirm that the growth bands are deposited annually. Marginal increments were significantly different between months (Kruskal-Wallis P < 0.001); a distinct trend of increasing monthly increment growth began in August. We estimated age in 425 cockles, which were collected from the Banquereau Bank (n = 240) and Grand Bank (n = 185). This data was used to determine the von Bertalanffy growth parameters for the 2 populations: L_∞ = 95.64 mm and 96.29 mm (Length), k = 0.21 and 0.17 and t_o = 0.97 and 0.33 for the Banquereau Bank and Grand Bank, respectively. There was a significant difference in growth curves between the 2 populations (Likelihood ratio test: X² = 33.40, P < 0.05). Minimum size and age at sexual maturity were 27.92 mm and 2.83 y for male tissues and 37.22 mm and 3.69 y for female tissues, respectively. This is the first time that age determination, growth, and minimum size of sexual maturity of the Greenland smoothcockle has been investigated.