The present invention relates to a device, system and method for determining vital signs of a subject. To improve accuracy and reliability, the device comprising a detection unit (30) for contactless detection of light in at least two different wavelength ranges from a region of interest of a subject, wherein said detection unit (30) is configured to detect a first light portion in a first wavelength range from light reflected from said region of interest in response to illumination by a first light source (22) and to detect a second light portion in a second wavelength range from light transmitted through said region interest in response to illumination by a second light source (24), wherein said detection unit (30) is configured to detect said first light portion and said second light portion simultaneously in response to illuminations that are at least temporarily simultaneous and wherein said first wavelength range and said second wavelength range are different. A processing unit (32) is provided for deriving plethysmography, PPG, signals from the detected light for said at least two different wavelength ranges. An analysis unit (34) is provided for deriving a desired vital sign from the PPG signals for at least two different wavelength ranges.
