In the field of fisheries, the analysis of the length-weight relationship (LWR) is the most commonly used one. Among several purposes for which it is used, the most popular is the estimation of weight from length. The present study was performed to analyze the LWR of Amblypharyngodon mola (Ham.-Buch., 1822), a freshwater cyprinid fish from an undisturbed wetland of Balarampur, Baruipur, West Bengal, India. The total length of the studied male specimens varied from 4.8 to 7.4 cm and that of female specimens from 5.1 to 8.9 cm. The body weight of male specimens was in the range of 1.02-3.64 g and that of female specimens 1.19-6.32 g. The calculated regression coefficient (b) values were 2.77, 3.09, and 3.25 for male, female, and combined sex fish, respectively. They indicate a negative allometric growth of male specimens and a positive allometric growth of female and combined sex specimens. Values of correlation coefficients (r) suggest a significant (p <0.01) positive relationship between length and weight in the studied fish. For male, female, and combined sex fish, "r" values were 0.950, 0.955, and 0.961, respectively. The present study provides baseline information on the LWR of A. mola, which will be beneficial for future management of this fish species. © 2015 Nature Research Centre.