A method for video evaluation of the heart rate and/or respiratory rate of a baby, in particular under dim or nocturnal conditions, in a device comprising a video camera and a source of infrared light, the method comprising the steps of:A1—illuminating the baby with the infrared source,A2—capturing video images of the baby,B1—determining the position of the baby's head by finding an ellipse forming an outline of the head,B2—identifying an area of interest centered on a selected ellipse,C—evaluating, by plethysmographic analysis of the area of interest, the heart rate and/or respiratory rate of the baby,and associated system.