Studies were conducted on 104 striped skunks, 97 raccoons, 64 opossums, 10 woodchucks, 5 feral cats, and 1 muskrat. Animals were trapped on an undeveloped forest and swamp area in Eastern Maryland. Leptospiral agglutinins were demonstrated in 62% of the skunks, 15% of opossums and 50% of the raccoons. Leptospiral serogroup members isolated from hosts were as follows: skunks — icterohaetnorrhagiae, grippotyphosa, ballum, and autumnalis; opossum — icterohaemorrhagiae and ballum; raccoon — icterohaemorrhagiae. Listeria monocytogenes was isolated from one raccoon. Significant complement-fixing antibodies for Rocky Mountain Spotted Fever group of rickettsia were demonstrated in 15% of 102 skunks, 18% of 94 raccoons, 40% of 10 woodchucks and in only 1 of 54 opossums. Isolates of a pox virus which appears to be a new type were obtained from upper respiratory tissues of two raccoons. Significant antibody titers for the isolated pox virus were demonstrated in 23% of 92 raccoon sera. Two isolates serologically related to infectious canine hepatitis (ICH) virus were isolated from pooled liver and spleen tissues of two skunks. Sera from 59 of 94 skunks had neutralizing antibody to the ICH isolate. Examinations of sera for antibody to influenza viruses A and B were negative. Complement-fixing antibodies for toxoplasmosis were demonstrated in 10 of 80 raccoons, and 3 of 7 woodchucks, but not in other species. Three types of microfilariae were seen in bloods of 29 of 104 skunks, 3 of 97 raccoons, and 1 of 61 opossums. During dissection of animals the guinea worms Dracunculus fuelleborni and Dracunculus insignis were found in three opossums and one raccoon respectively. Lung flukes (Paragonimus kellicoti, syn. P. rudis) were found in three skunks.