Radioactive contamination of soils pose a serious impact on the properties of soils and thereof effect the productivity, health of organisms thus effect the biodiversity. Hence the identification, analysis and remediation of radioactive contamination of soils plays a vital role. Therefore in this chapter, the emphasis is given on understanding the nature of radioactivity and radioactive substances, their half-life, behaviour in soils, their effects and remediation. There are various agencies and committees like IAEA, UNSCEA that work on radioactivity.