This presentation describes the year-round school operation of the Chula Vista City School District in California. Chula Vista adopted the 45-15 year-round plan to help ease a shortage of classroom space while maintaining a quality program for children. Under the plan, each pupil attends school for about nine weeks and then has vacation for three weeks. Throughout the year, one-fourth of the pupils are on vacation at any time. Major advantages of the year-round program are that the long summer vacation is redistributed into shorter seasonal vacations, the school facility is in use 12 months a year, variations in teacher contracts are possible, and most of the benefits of the traditional school program are retained. Disadvantages include the break in the tradition of a long summer holiday, difficulties in scheduling and communication, more expensive maintenance, and the need to study and consider vacation programs throughout the entire year. The document also considers answers to questions often asked about implementation of a year-round school program. The 1974-75 year-round school calendar for each student group is included. (Author/DN)