An early hominid skull found in Petralona Cave in Greece has been widely quoted by the archaeologist now excavating the cave as being about 700,000 years old. A recent volume of the journal Anthropos (Athens) carried several papers dealing with uranium series, thermoluminescence, electron spin resonance and palaeomagnetic studies on material from Petralona. Careful reading of these papers shows that there are problems with all these methods when applied to material from this site and that it is not possible at present to give an age for deposits in the cave. This paper discusses each technique in the light of current knowledge.