Bottom waters from five hydrographic stations, spaced equally along a 400-km section of the Juan de Fuca Ridge north of the Blanco Fracture Zone, contain anomalously high concentrations of total dissolvable manganese (TDM). The two bottom-most bottles from each hydrocast (~ 100 to 200 m above bottom) range from 8.3 to 108.9 nmol kg-1 with a median value of 12.0 nmol kg-1. This median is nearly a factor of 10 higher than similar near bottom samples obtained from two off-axis locations. Analogy to work on the East Pacific Rise implies that hydrothermal activity along the ridge axis is contributing substantially to the manganese content of the water column in this portion of the northeastern Pacific.