A casual labour market is an open-air market in casual, unskilled work for day labourers. The casual labour market in Budapest's Moszkva ter, despite major differences, resembles in many ways those in other big cities (Tokyo, New York and Los Angeles), for instance in the dominance of heavy manual, mainly casual construction work, the illegality, and the dominance of men in poor social conditions. Altogether 84 'nonparticipant' observations were made in two observation periods, 1995 and 2004. These were representative in terms of day, season and time of day. Immutability in the supply and demand on the Moszkva ter casual labour market can be shown in the decisive elements of the casual labour market as an institution: the structure of labour supply (young, commuting or migrant young men of low education accounted for the bulk of the employed throughout) and the transaction mechanism (public, tolerant police control, group bargains). Change can be seen in the frequency of the transactions: the market shrank, but the supply (the number of employees) fell less than the demand (the number of offers), so that chance of obtaining work declined and pay fell. So the casual labour market offers to the labour market participants most heavily discriminated against the kind of black market work opportunities that are ever more poorly paid and uncertain and do not lead to regular employment.