Two long series of samples from Tikal, Petén, Guatemala, have been dated by the radiocarbon method for the purpose of limiting the range of possible correlations of the Maya calendar with the Christian. These samples from lintel and vault beams were selected from latest-growth portions of the beams which were presumably cut at times corresponding to Maya dates carved on lintels of two temples. Christian dates for dedicatory Maya dates of the lintels are calculated according to five correlation hypotheses, and are compared with radiocarbon dates for ten beams from Temple IV and six from Temple I. These new radiocarbon dates are shown to be closely related to “absolute” ages by means of radiocarbon counts of tree-ring-dated samples of the same period. The radiocarbon results support the 11-16 (Goodman-Thompson-Martinez) correlation. Attention is given to previous radiocarbon tests by other laboratories of beams removed from Tikal many years ago which seemed to favor the 12-9 correlation in Spinden or Makemson variants. With the aid of new radiocarbon dates for similar samples, reasons for the differences in results are discussed.