Over the last few decades, minimally invasive treatments have gained large interest as alternative to surgical resection. Among others, thermal treatments have broad clinical acceptance for treating a number of solid tumors. In this context, the knowledge of temperature during the treatment may be useful to improve the clinical outcomes. The aim of this work is to assess the feasibility of two multipoint probes for temperature monitoring during laser ablation (LA). The probe consists of a medical needle which embeds an array of 7 fiber Bragg grating (FBG) sensors. Experiments, performed in in vivo animal model (pig liver), show that the probe is able to reach deep organs and gives the possibility to monitor the tissue temperature in several points. This information may be crucial to guide the clinicians in the optimization of treatment settings, as well as to improve the accuracy of theoretical models that will guide future study to design new heating device and to develop patient-specific treatments.