The present investigation has been achieved as an attempt to study the influence of climatic change on the population density of land snails Monacha cartusiana ,Monacha cantiana , Cochilicella acuta , Succinea putris , Succinea oblonga and gray garden slug Deroceras reticulatum under lemon and guava trees at ElSenania and Kafr El-Batikh districts,Dumyatt Governorate 2011/2012 and 2012/2013 seasons .       The results revealed that the mean of populations density were higher throughout spring season followed by autumn and lower in winter seasons which estimating by 35.8, 29.3 and  18.5 snails/sample  for M. cartusiana, respectively . C.acuta recorded the higher number on lemon trees 57.2 in spring season while recorded 45.2 in autumn season followed by winter season which recorded 25.6 snails/sample.        The population fluctuations of land snails varied according to crop , temperature , relative humidity and season to another . The snails were more active during spring and autumn .The snails C.acuta were the highest number of individuals on lemon and guava trees.  Key words: seasonal, fluctuation of land snails and slugs, lemon , guava                                                     trees , Dumyatt. Temperature.