Traditionally,rice production in Thailand is carried out by means of manual operation as well as using animal labor,which are adequate for small scale farm and field cultivation.With land reform,more land has been allotted for industrial development,resulting in labor shortage in agricultural sector.Mechanization in rice production became more important and developed,especially in the irrigated area.Due to double cropping system,mechanization expanded rapidly both in number and in size of the machinery used.The purpose of this paper is to study the developmental stage of Thai rice mechanization in connection to rice production patterns,soil preparation,planting,chemical and fertilizer application,harvesting and drying.The study quotes from the data by Office of Agricultural Economic (OAE) and Agricultural Engineering Research Institute (AERI).The data was analyzed by comparing mechanization statistics taken from 1998 to 2008.There are two rice production patterns: The first is the irrigated-area pattern which is almost fully mechanized.The second is the non-irrigated-area pattern which can be developed further for mechanization.Soil preparation is fully mechanized in both patterns.Planting in the irrigated-area is more mechanized than in the non-irrigated-area.Crop protection mechanization in both patterns needs more developed.Harvesting-threshing in the irrigated-area was operated by combineharvester with hire service system while in the non-irrigated-area,manual harvesting and thresher were employed.Drying was carried out by cooperative groups and private millers.The mechanization in rice production advanced gradually from simple equipment such as tillage,thresher,transplanter and combineharvester.Mechanization is not only advantageous compensating for labor shortage,timeliness but also profitable by increasing production as well as reducing cost production.The decade has seen an expansion of the extent of mechanization both in number and in size of machinery: For example,with walking tractor there has been a 25.63 % increase and with riding tractor,50.27 % increase.With knapsack sprayer there has been an 8.37 % reduction,while the use of engine sprayer increased by 40.63 %.The use of combine harvester increased 90 % or more.On the other hand,most of the machinery for rice production is of local manufacture,except for some complicated machines which are imported.Rice production in Thailand can develop to full mechanization in both in the irrigated and non-irrigated areas.Development from the basics in each area should continue with optimization of mechanization.The mechanization policy must persist.