Introducing microbubbles in a microreactor for continuous crystallization increases the nucleation rate and also prevents clogging. Adding surfactants affects the microbubble generation as it reduces their size, increases their frequency of formation and consequently also the interfacial area per unit volume of reactor acting as heterogeneous surface for nucleation. Here, the effect of sodium dodecyl sulfate (SDS) on both the microbubble generation and the continuous crystallization of paracetamol is investigated. It is observed that while SDS significantly enlarges the heterogeneous surface available for nucleation, the crystallization itself is inhibited by its presence.