Shock probation, a rehabilitation technique by which a defendant is given a brief taste of prison or jail and is then placed on probation for the remainder of the sentence, was authorized by the legislature effective August 19, 1977. Of the 87 departments responding to the survey (out of 106 queried), 75 reported having used shock probation. From these 75 departments, 1078 adults were placed on shock probation during the time span from August 29, 1977 to April 8, 1980. Of this number, 808 are still on probation, and 221 had unsuccessful probations. Survey responses indicate that prior knowledge of subsequent shock probation by the defendant is an important factor in this approach; 66 percent of the departments expressed the opinion that in order for shock probation to be really effective, a defendant should not be informed of being placed on shock probation until recalled from incarceration. In constrast, it was reported that 65 percent of all felony shock probationers had prior knowledge of subsequent shock probation. The effectiveness of shock probation was rated in various ways. Overall, 71 percent of the responding departments rated shock probation as effective, 22 percent thought it too soon to evaluate the effectiveness, and 5 percent thought it was not very effective. Concerning the impact of shock probation on the prison population, it was estimated that approximately 64 percet of the shock probationers would likely have been incarcerated for sentence duration if shock probation had not been available. Two footnotes, three tables, and five figures are provided in the survey. (Author abstract modified.