The Spanish Socialists have held onto power in Andalusia but the new anti-austerity party Podemos has made significant gains in the region.
Podemos came third in Sunday's regional election, challenging the grip of the Socialists and the conservative Popular Party (PP), which rules nationally.
The vote was seen as an important barometer of opinion ahead of national elections later this year.
Podemos - meaning "we can" - got 15 of the 109 seats contested in Andalusia.
The southern region was hit especially hard by Spain's property crash and debt crisis, and has the country's highest unemployment rate - 34.2%. The region's economy is dominated by agriculture and tourism.
The Socialists (PSOE), who have governed Andalusia for more than 30 years, got 47 seats and the PP 33.
Podemos, a leftist grassroots movement launched in January 2014, unexpectedly won five seats in last May's European elections.
The Podemos leader in Andalusia, Teresa Rodriguez, said "we are the protagonists of change... The political map in Andalusia and Spain has changed".
Another new party challenging Spain's decades-old pattern of two-party rivalry, Ciudadanos (meaning "Citizens"), finished fourth with nine seats. Ciudadanos has a pro-business agenda, and is seen as a threat to the PP.