Computer assisted instruction (CAI) may well represent the next phase in the involvement of the library or learning resources center with media and the educational process. The Lister Hill Center Experimental CAI Network was established in July, 1972, on the recommendation of the National Library of Medicine, to test the feasibility of sharing CAI materials through a national computer network. Three suppliers of CAI programs--Ohio State University, the Massachusetts General Hospital, and the University of Illinois Medical Center in Chicago--combined with one commercial time-sharing corporation to realize the network concept. CAI programs on the network are applicable to health science users at all levels and have been utilized by over 100 health science institutions. The network was initially free to users. While the institution of charges caused an initial drop in the number of users, their numbers have risen again, and the network is now self-supporting. This network method may be too expensive to allow most libraries to make effective use of CAI, but costs could be cut through the use of minicomputers and intelligent terminals. (Author/SL)