Abstract Monitoring piglets’ temperatures after birth is crucial to prevent losses caused by hypothermia and ensure well-being. Rectal measuring, which is still considered the ‘gold standard’ for assessing core temperatures, takes time and requires fixation. Aim of this study was to evaluate the effectiveness of infrared thermography and thermometry in comparison to rectal temperatures. In one to seven days old piglets, rectal temperatures were measured with digital thermometers (DT) (Geratherm® GT-195-1) (n = 958), tympanic membrane temperatures with an infrared ear thermometer (IET) (ThermoScan® IRT6520) (n = 424), skin temperatures with infrared laser thermometers (ILT) (Eventek™ ET312) behind the ear (n = 671), an infrared camera (IC) (Optris® PI400) at six body locations (n≥488) or an infrared camera attachment (ICA) (FLIR ONE® for iOS) (n = 60). Devices’ reliability was tested. Correlations and differences (GLM) were estimated with SAS® 9.4. DT devices and repeated measurements showed no differences (n = 77). Repeated IET measurements at left and right ear were not different (n = 57). Temperatures decreased for ILT when measured from 10, 30, 50, and 100cm (P < 0.001; n = 360). Three ILT devices obtained different values (P < 0.001). At 10cm, means were different at left and right side (P < 0.001). For following results, the same device was used for all measurements (10cm, left). Highest correlations were found between DT and IET (r = 0.93; P < 0.001) and ILT (r = 0.81; P < 0.001). All infrared temperatures were lower (P < 0.001) than rectal temperatures (38.8°C), except IET (38.7°C). For IC, temperatures at inner thigh and lower abdomen correlated best with DT (0.59≤r≤0.62; P < 0.001). IET seems suited for assessing temperatures in piglets as it is reliable, with values comparable to DT. For IC, inner thigh and lower abdomen seem promising locations, but fixation is still required for both techniques. ILT is an option for estimating core temperatures at a short distance, but reliability needs to be considered.