Introduction. The date palm tree is one of the fruit trees most cultivated in the Arabian Gulf States.Bioregulators were used for the quality and productivity improvement of date palm tree fruits. A study was conducted toassess the relative effectiveness of GA3, NAA, ethephon and a mixture of growth regulators on some fruitcharacteristics and productivity of the Barhee date palm tree cultivar. Materials and methods. Five selectedfemale uniform date palm trees of the cultivar Barhee were pollinated on March 5-15, 1994, 1995 and 1996, by placingeight fresh male strands on the female spadix center (flower cluster).Ten flower clusters were used on each tree anddivided into five groups of two flower clusters. Each of these groups was subjected to one of the following treatments:control (water), 150 mg GA3 × L-1, 100 mg NAA × L-1, 1 000 mg ethephon × L-1 and a mixture of these three growth regulators. Then the fruit setting, fruit flesh and dry matter percentages,the total soluble solids, the fruit ripening, and the fruit weight per bunch and per tree were measured. Resultsand discussion. The data showed that the application of GA3 or ethephon on flower clusters of Barhee date palm treeshad no constant effect on fruit characteristics and productivity of trees. NAA or growth regulator mixture applicationson Barhee flower clusters reduced the fruit dry matter and fruit ripening percentages and increased the fruit weight perbunch and per tree. Conclusion. Treatments of Barhee date palm flower clusters, 20 d after pollination, with NAA or thespecific growth regulator mixture decreased the dry matter percentage and the fruit ripening and increased the fruitflesh percentage and the date palm tree yield, therefore, these treatments could be recommended to improve theproductivity of date palm trees in the region.