<p><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:14px">&ldquo;Limnology&rdquo; a new interdisciplinary science with multifarious dimensions has emerged which deals with the study of structural and functional attributes of the lentic </span></span><span style="font-size:14px"><span style="font-family:Verdana"><span style="font-family:Arial,Helvetica,sans-serif">fresh water</span><span style="font-family:Arial,Helvetica,sans-serif"> environment and problems associated with them. Limnology has immense and universal significance for the citizen of today, all around the world. Streams, rivers, wetlands </span><span style="font-family:Arial,Helvetica,sans-serif">and</span><span style="font-family:Arial,Helvetica,sans-serif"> lakes are home </span><span style="font-family:Arial,Helvetica,sans-serif">for</span><span style="font-family:Arial,Helvetica,sans-serif"> many small animals called </span><span style="font-family:Arial,Helvetica,sans-serif">macro invertebrates</span><span style="font-family:Arial,Helvetica,sans-serif">. The term macro invertebrates describe those animals that have no </span><span style="font-family:Arial,Helvetica,sans-serif">back bone</span><span style="font-family:Arial,Helvetica,sans-serif"> and can be seen with naked eyes. This study includes analysis of identification of invertebrates in Anasagar Lake in Ajmer (Raj.).The methodology employed involves </span><span style="font-family:Arial,Helvetica,sans-serif">collection</span><span style="font-family:Arial,Helvetica,sans-serif"> and identification of invertebrates with the help of various </span><span style="font-family:Arial,Helvetica,sans-serif">equipments</span></span></span><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:14px"> and tools. The result has been presented in form of a key of freshwater invertebrates of Anasagar Lake of Ajmer.</span></span></p>