Abstract: All countries of the world are vulnerable to climatic variations and change, and developing countries especially, those in arid, semi-arid and high rainfall regions, are particularly so. Africa is considered the most vulnerable region in the world in terms of climate change and variation, due to its physical and socio-economic characteristics. Climate variation generally occurs at local scale, regional scale, national scale and global scale. Having established that the global climate has varied slowly over the past millennia, centuries, and decades it is expected to continue to vary in future. Like the climate change, variability may be due to, national internal process within the climate (internal variability), or variations in natural or anthropogenic external forces (external variability). Evidence of climate variations is now well documented, and the implications are becoming increasingly clear as data accumulates and data and climate models become increasingly sophisticated. The fluctuations in rainfall and temperatures regimes are basically the atmospheric deriving forces that are responsible for the climate variations over Imo State and the entire southeastern part of Nigeria as the case in other regions of the world. This paper examines the impacts of climate variability and change in Imo state of Nigeria. The study employed the use of 30 years (1980-2009) precipitation (rainfall) and temperature data of Imo state recorded at Owerri (the capital) synoptic station which was acquired from Nigerian Meteorological Agency (NIMET). The study shows a lot of variation in rainfall and fluctuation in temperature in the area within the period under study, which have caused a lot of environmental problems in the state including sea-level rise, increased heat wave, increased coastal/soil erosion, flooding and flood –related disasters such as pollution, increased diseased vectors, communicable diseases and epidemics amongst others.