Scholars have argued that learning science is linked to a decrease in personal faith among scientists. We do not know much, however, about the so-called secularizing effect of science among scientists outside the US, where such religious processes could operate differently. Because the negotiation between science and religion is more salient when faith is in transition, we examine how scientists in Italy (a predominantly Catholic context) construct religious identity during religious shifts. Drawing from interviews with 81 Italian physicists and biologists, we ask whether scientists have experienced any religious shifts and how they went through these shifts, addressing personal secularization theories by analyzing whether and how scientists reconstruct their religious identities by utilizing science. We uncover four patterns of identity construction: constructing a non-religious identity, forming a spiritual identity, reformulating an existing Catholic identity, and re-achieving a Catholic identity. We show that Italian scientists narratively respond to Catholicism more than science in constructing religious identities during religious shifts. Our findings, thus, problematize the so-called personal secularizing effect of science, providing implications for a more fruitful dialogue between science and religion in Italy and more globally.