The Argentinian insists the superstars would not score 80-90 goals if they played in Italy.
But his numbers pale before the exploits of Messi and Ronaldo, who hit the target more than 50 times in a season on a regular basis.
"I will say that in Italy there is much better defending and it's a tactical type of football," FourFourTwo quoted Dybala as saying to Tuttosport.
"The little clubs do not play in a wild and careless way as they do in Spain, although Atletico Madrid are changing this mentality. Messi and Cristiano Ronaldo would not have scored 80-90 goals in Italy. Perhaps they would get 40 like [Gonzalo] Higuain but not 80."
Having spent two months sidelined this season, Messi has a tally of 37 goals for Barcelona in all competitions this season while Ronaldo has scored 47 so far.