The impact of one-stop career centers on the U.S. Employment Service (ES) program was examined through case studies of one-stop initiatives in the following states: Georgia; Ohio; California; Iowa; Oregon; Massachusetts; Texas; Utah; and Wisconsin. Of the nine case study states, only Georgia had not begun instituting a one-stop career center system as of 1997. Ohio, California, Massachusetts, and Oregon were using various forms of interagency agreements to foster cooperation of ES with job training and other agencies at one-stops. Iowa, Utah, Wisconsin, and Texas had created new consolidated agencies. The following were among the 17 conclusions and suggestions emerging from the study: (1) state legislation should continue to encourage workforce service agency consolidation; (2) the ES must have the lead role in one-stop centers; (3) however state agencies are organized, one-stops should provide integrated services for the greatest number of programs possible; (4) strategies to involve employers in state workforce development activities should be emphasized; and (5) the ES's role in ensuring prompt reemployment of unemployment insurance recipients needs continued emphasis. (A table detailing selected ES productivity and funding measures in the nine case study states and nationwide and a discussion of consolidated workforce development agencies are appended.) (MN)