For years, the issue of technological unemployment has been banned from respectable economic discourse and any prevision related to the unwanted effects of automation has been branded as “the Luddite fallacy”. In the second decade of the 21st century, a growing number of analysts prognosticate a future of mass unemployment, as a consequence of robotization and computerization. Although without using this expression, Karl Marx wrote much about technological unemployment. In contrast to classical political economy, he especially stressed the bodily and mental suffering produced by this phenomenon, and the fact that its temporary character is of no consolation for the poorer classes. Besides, he provided economic theory with a cluster of ideas related to technological unemployment, such as “reserve army of labor”, “liquid work”, “technological underemployment”, and “compensation”, which constitute a useful toolbox still used by analysts. What sometimes is lacking is the awareness of the Marxian origins of these ideas.