Conscientious objection in the healthcare professions was a topic that Gonzalo Herranz addressed early on and with a very particular perspective. At all times he moved away from a strictly legal discussion to delve into the real grounds that justify a healthcare agent's refusal to submit to a certain rule, considering that it goes against his or her conscience. This article presents some of the main issues that Professor He- rranz addressed in his publications and conferences in relation to conscientious objection.