In 1976, Viking missions to Mars performed three independent experiments to detect signs of life in the Martian soil. The Labeled Release experiment (LR) monitored the evolution of radiolabeled gas, most likely CO2, after injection of a 14C-labeled nutrient mixture. The release process was characterized by an energy of activation of 35-43 Kcal/mole, i.e. within the range of a biologic process, and the sterilization of Martian soil prevented the release. Miller, Straat and Levin (2002), analyzing the periodic fluctuations of the radiolabeled gas, detected a circadian rhythm that may further support a biologic interpretation. However, a highly correlated periodic oscillation in the temperature inside the chamber test didn’t permit a claim of “fi nal proof” of the presence of putative Martian microorganisms. To test the hypothesis of a biologic origin of the gas released by the LR experiment, we have performed a complexity analysis of the radiolabeled gas evolution and temperature data published by Miller and co-workers. Our results permit separation of the two parameters, and, much more, fi nd that the fl uctuations of the radiolabeled gas perfectly overlap the fl uctuations present in physiologic processes, like the heartbeat in a neonate, supporting the biologic origin of the radiolabeled gas release from Martian soil. A more intensive analysis now underway will investigate this matter further in the hope of reaching a fi nal conclusion about whether the Viking LR detected life on Mars as has been claimed by Levin