Castleford are still without a league win this season after finding early pacesetters York too strong in the Yorkshire Premier North.
York took just three hours to record an eight-wicket victory at Savile Park after Castleford suffered a batting collapse.
After electing to bat first, Castleford lost opener Connor Hyde to the first ball, but then seemed to be making steady progress as Luke Edwards (17) and Liam Hyde (26) put on 42 for the second wicket.
They reached 58-2 before the fall of Edwards signalled a downward spiral and the last eight wickets went down for only 41 runs with the hosts all out for 99 in 36.1 overs.
Skipper David Wainwright stuck it out for 78 balls, scoring 31, but none of the remaining batsmen could reach double figures against a strong bowling attack led by Charlie Elliot (3-31), Jack Leaning (3-20) and Tom Pringle (3-10).
Leaning then finished unbeaten on 47 as York continued their unbeaten start, reaching their target in less than 20 overs for the loss of two wickets, one each to Connor Hyde and Eddie Morrison.