Temperature, gas and humidity resistive/ capacitive sensors on flexible substrates from organic materials, suitable for RFID mobile applications, have been produced and investigated. The sensor implementation solutions are providing simple, versatile and low power temperature and gas detection. The device structure was developed together with the data evaluation strategies based on last generation SigmaDelta analog (resistance and capacitance) to digital converters. We demonstrate the possibility of developing gas sensors on humidity sensitive substrates, having temperature corrected responses. The proposed device concept is aimed to evolve towards "flexible & full plastic" implementations.