In this paper, sufficient conditions for chaos in non-linear sampled-data control systems are investigated by applying Marotto's (1978) Theorem and Shiraiwa and Kurata's (1980) Theorem. It is shown that a state-feedback sampled-data control system with sampling periodTis chaotic ifT >T*for sufficiently largoT*. It is also shown that if a sampled-data control system has an output-feedback and can be split into two subsystems, the existence of chaos in the system can be checked only by the lower-dimensional subsystem behaviour.