The Communications index, which makes up 3.82 percent of the basket of goods used to measure inflation, fell by 23.5 percent when compared with July, and by 24.1 percent when compared with August 2009.
"The Communications' index declined ... on account of significant falls in the cost of airtime in addition to continued decline in the cost of handsets," Kenya National Bureau of Statistics (KNBS) said in a statement.
"The average cost of airtime per minute dropped by more than 50 percent for customers procuring the services from major cell phone operators."
In recent days mobile phone operators in Kenya have slashed their calling rates following a cut in interconnection fees by regulator Communications Commission of Kenya.
The statistics body said month-on-month food and non-alcoholic drinks prices rose by 1.9 percent between July and August.
"This was attributed to the aggregate rise in the prices of a number of food items outweighing falls in the prices of others. Some of the food products which recorded price increases include: Milk, sugar, potatoes and wheat flour," KNBS said.
"On the other hand there were significant falls in the prices of maize flour and maize grain."
Food makes up 36.04 percent of the basket of goods used to gauge inflation.
A Reuters poll of 10 economists and analysts showed in mid August that Kenya's headline inflation was seen coming in at 4.3 percent at the end of 2010, and 6.3 percent in 2011.
