Accurate charting of marine fog distribution is made difficult because of the sparseness of transient-ship observations. The meteorological satellite offers the possibility of improving fog diagnosis by specifying areas vice a discrete number of points of marine fog. The study explores the feasibility of using meteorological satellite data, visual andor infrared, as means of discerning the presence of marine fog. Transient-ship and satellite data from a summer-season period in 1973, eastern North Pacific Ocean, served as data base. A qualitative comparison is made between NOAA-2 satellite imagery and verifying marine fog, as determined from the synoptic-time ship data qualitative guidelines for diagnosing the presence of marine fog from the visual and infrared imagery were formulated. A quantitative determination of the presence of marine fog, using visual and infrared NOAA-2 digital satellite data, is presented, from which a technique is developed for objectively diagnosing regions of marine fog.