Memory controller and memory system including the same

A memory controller, to control a semiconductor memory device, includes an access pattern profiler, a row hammer prediction neural network, and a memory interface. The access pattern profiler generates an access pattern profile based on a row access pattern on a portion of memory cell rows of the semiconductor memory device during a reference time interval posterior to a refresh interval during which the memory cell rows are refreshed. The row hammer prediction neural network predicts a probability of occurrence based on the access pattern profile. In response to the probability being equal to or greater than a reference value, the row hammer prediction neural network generates a hammer address, an alert signal indicating that the row hammer occurs, and an outcast row list. The memory interface transmits the hammer address, the outcast row list, and the alert signal to the semiconductor memory device.