INTRODUCTION As stated in a previous progress report (Nelson, 1977), “The Division of Operational Safety or DOS (now Safety Standards and Compliance) portion of the Laboratory of Radiation Ecology (LRE) Pacific Radioecology Program (formerly Johnston Atoll Program) began on 1 July 1974 and is continuing. The purpose of this program is to determine the kinds and amounts of radionuclides distributed in the foods, plants, animals, and soil of the Central Pacific, especially the Marshal] Islands, and to furnish these data to SSS/ERDA and other appropriate agencies (Lawrence Livermore Laboratory, Nevada Operations Office ERDA) so that they may make an assessment of the dose of ionizing radiation received by the people living throughout the Central Pacific." Here we report the results of the analyses of samples collected on a field trip conducted in September-October 1976. SAMPLING PROGRAM Atolls visited in the Marshall Islands are shown in Figure 1. This trip was a joint survey with personnel from Brookhaven National Laboratory. Representative biological and soil samples were collected with emphasis on food items common to the diet of the Marshallese people (i.e., fish, coconut, pandanus, breadfruit, coconut crabs, etc.) although nonedible portions of these items were also collected and analyzed. Soils were collected to provide data for estimating future distribution and quantities of radionuclides in the environment and biota. Sampling sites are shown in Figures 2 through 5. The number of samples, after division into tissues or soil fractions, is shown in Table 1. Slightly less than half the samples were biota-plants, fish, clams, and coconut crabs - and the rest were soils - surface (0-2.5cm) and profile (0-100+cm).