Candidatus Liberibacter asiaticus (CLas) is an unculturable, phloem-limited gram-negative bacterium associated with citrus Huanglongbing (HLB) disease in Florida and most other citrus-producing countries around the world. HLB is considered the most destructive disease of citrus and is severely affecting the fruit production worldwide. Natural transmission of CLas occurs by the Asian citrus psyllid (ACP) vector Diaphorina citri. Under greenhouse conditions, the experimental transmission of CLas to non-infected trees usually is accomplished using infected ACP or by grafting infected citrus tissue. CLas was confirmed infecting citrus in Florida in 2005 and many characteristics of the disease have been described. However, the transmission of CLas for controlled greenhouse studies is often prob lematic and poorly understood. Due the complexity in maintenance of ACP colonies for controlled vector transmission, the experimental infection of new plants is accomplished primarily by grafting, but several factors may influence the reliability of this method. This study evaluates the propagation and transmission efficiency of CLas using graft inoculation methods under greenhouse conditions. Three experiments were conducted for with graft inoculation: 1) seedlings of 12 cultivars; 2) ‘Tango’ mandarin on 13 rootstock cultivars; and 3) ‘Navel’ orange on 14 rootstock cultivars. Plants were inoculated with buds from infected greenhouse-grown ‘Valencia’ orange plants that were poly merase chain reaction (PCR) positive for CLas and symptomatic for HLB. Three bud pieces were used to inoculate each plant using the inverted-T method.