Data have been tabulated from more than 150 references on the solubility of inert gases in fluids and tissues of biological interest. Thirty-two gases have been studied in blood with measured solubility ranging from 0.005 to 16 ml of gas at 37 degrees C per ml of blood per ATA (Ostwald coefficient). For most gases, solubility in other tissues such as muscle or brain is between 60% and 300% of blood solubility. Measured solubilities in biological tissues do not correspond well to solubility in water and oil. Most gases decrease in solubility by 1%-6% for each degree C rise in temperature. The effect of pressure on solubility has not been well studied, and only crude estimates can be obtained by using methods of chemical thermodynamics.