In the 1970s, Miltiadis Grigoriou was one of the leading Greek chess players. In 1974 he won Greek Chess Championship.[1] In 1978 he won 3rd place in International Chess tournament in Kallithea, scored 6½ out of 11, one and a half points behind the tournament winners Petar Velikov and Krum Georgiev.[2]
Miltiadis Grigoriou played for Greece in the Men's Chess Balkaniads:[3]
- In 1975, at second board in the 7th Men's Chess Balkaniad in Istanbul (+1, =2, -1),
- In 1976, at second board in the 8th Men's Chess Balkaniad in Athens (+1, =2, -1) and won individual bronze medal,
- In 1977, at sixth board in the 9th Men's Chess Balkaniad in Albena (+0, =2, -2) and won individual bronze medal,
- In 1979, at sixth board in the 11th Chess Balkaniad in Bihać (+1, =2, -2).
In 1975, Miltiadis Grigoriou was awarded the FIDE International Master (IM) title.
