The entomopathogenic fungi Beauveria bassiana, Lecanicillium dimorphum and L. cf. psailiotae can survive and colonize living palm tissue as endophytes. The molecular interaction between these biocontrol agent fungi and the date palm Phoenix dactylifera L. was investigated using proteomic techniques. Field date palms inoculated with these fungi were analyzed 15 and 30 days after inoculation in two independent bioassays. In vitro date palms were also inoculated with B. bassiana or L. cf psalliotae. Qualitative and quantitative differences in protein accumulation between controls (not inoculated) and inoculated palms were found using 2-DE analysis, and some of these responsive proteins could be identified using MALDI/TOF-TOF. Proteins involved in plant defence or stress response were induced in P. dactylifera leaves as a response to endophytic colonization by entomopathogenic fungi in field date palms. Proteins related with photosynthesis and energy metabolism were also affected by entomopathogenic fungi colonization. A myosin heavy chain-like protein was accumulated in in vitro palms inoculated with these fungi. This suggests that endophytic colonization by these entomopathogenic fungi modulates plant defence responses and energy metabolism in field date palms and possibly modulates the expression of cell division-related proteins in in vitro palms at proteomic level.