The article provides new evidence on the effects of a major shock to deterrence on crime. The collapse of communism in the Czech Republic in 1989 was followed by sharp reductions in the probability and severity of punishment and by sharp increases in crime rates. I investigate whether deterrence was a significant contributor to the post-1989 growth in crime on a panel dataset of Czech regions. The results show strong deterrence effects for robbery, theft and intentional injury, but not for murder and rape. About 25% of the increase in robberies and 50% of the growth in thefts is accounted for by weaker deterrence.