Using his video blog on the Kremlin website to wade into a debate that still divides Russia more than half a century after Stalin's death, Mr Medvedev said it was wrong to be an apologist for someone who had destroyed their own people and sent millions of innocents to die in the gulag or be shot.
"Even now you can hear people say that what happened to the many victims was justified by certain higher government aims," said a sombre-faced Mr Medvedev.
"[But] nothing can be placed higher than the value of human life. There can be no justification for the repressions."
It was vital to remember and mourn the millions of victims, he added.
Mr Medvedev's words will anger many older Russians who still hero-worship Stalin, arguing that he masterminded the Soviet defeat of Nazi Germany and turned the country into a superpower.
Hmmm...sure it sounds good, but this is Medvedev, a Putin puppet. Putin is himself a huge fan of Stalin. So what gives? What's the motivation here? If anyone has any thoughts, please enlighten me.