This book deal with compounds that never had been studied in Iraq called taste and odour compounds, two species of cyanobacterial strains were identified as producers for these compounds, the first was Phormidium retzii produced geosmin and Microcoleus vaginatus produced 2-Methylisoborneol which were recorded for the first time in the world as a producer. These two compounds were detection by Solid phase microextraction method coupled with GC/MS and genetic analysis by six primers designed for detection of genes responsible of geosmin production by Phormidium retzii and 2-Methylisoborneol production by Microcoleus vaginatus by PCR technique which were geo1, geo2, geo3 and 2-MIB1, 2-MIB2, 2-MIB3 derived from cyanophyta species exist online in National centre of biotechnology information (NCBI) site were discovered before which were producing geosmin and 2-Methylisoborneol. The primers gave good consequences for detection the genes responsible of these two compounds. Four environmental factors (temperature, light intensity, phosphate and nitrate) were used to notice their effects on geosmin and 2-MIB production by these two cyanobacterial strains.