The author considers some aspects of slave labour in Athenian public construction using reports concerning Erechtheum and Eleusis. Special attention is paid to verification of V.D. Kuznetsov’s thesis concerning the character of this labour. The author comes to the conclusion that there was no necessary connection between the status of slave labour and pay by the day received by privately owned slaves. He puts forward a hypothesis that the forms of hire and pay implying material incentive were supported by slave owners. As far as one can see from the documents, slaves were often engaged in skilled labour. In spite of some scholarly opinions, the presence of slaves’ names in Erechtheum reports depended on technical, not ideological reasons. There are some grounds to think that during the construction of Erechtheum free artisans used unknown assistants, mainly slaves, when they did piecework and work paid for individually, while in the works paid by the day and in brigade works all the workers – even anonymous – were taken into account. The fact that the greatest part of workers is either anonymous or not mentioned Eleusinian inscriptions is explained by the fact that Eleusis was built mainly by contract. Another hypothesis put forward here considers the connection between pay by the day and the term oikositoi (home-fed) used in Eleusinian reports. To conclude, the author notes that the Athenians’ unwillingness to work for pay by the day did not become less when the state acted as employer. Work by the day must have been associated with slave labour.