  We investigate the instanton dynamics of asymptotically safe and free quantum
field theories featuring respectively controllable ultraviolet and infrared
fixed points. We start by briefly reviewing the salient points about the
instanton calculus for pure Yang Mills (YM) and QCD. We then move on to
determine the role of instantons within the controllable regime of the QCD
conformal window. In this region we add a fermion-mass operator and determine
the density of instantons per unit volume as function of the fermion mass.
Finally, for the first time, we extend the instanton calculus to asymptotically
safe theories.
