Of Argentina's five big clubs, only Boca has never been relegated. The other four went down once each: here is when, how and how many seasons they spent in the second division.
The five big clubs, debut to today
Boca Juniors
Independiente2nd div. 2013/14
Racing Club2nd div. 1984–1985
River Plate2nd div. 2011/12
San Lorenzo2nd div. 1982
193019501970199020102026
First divisionSecond division
Every relegation, in order
Relegated1981
San Lorenzo
How
Last two places of the league table, together with Colón
Bottom of the tableSan Lorenzo went down in 1981 for finishing in the last two places of the table, with Colón.
AveragesIn 1983 relegation by averages came back: points of the last three seasons over games played. Racing went down that year; Independiente fell the same way in 2012/13.
Play-offIn 2010/11 the two worst averages went straight down, and the next two played a home-and-away play-off against second-division sides. River lost theirs to Belgrano.
How long each one lasted
Club
Down
Second division
Back for
San Lorenzo
1981
1982
1983
Racing Club
1983
1984 and 1985
1986/87
River Plate
2010/11
2011/12
2012/13
Independiente
2012/13
2013/14
2014
Seasons as Wikipedia writes them. With the tournaments being reorganised, Racing also missed the 1985 Nacional.
On Jun 26, 2011, drawing the second leg of the play-off with Belgrano after losing the first. River played 2011/12 in the second division and came back for 2012/13.
Has Boca ever been relegated?
No. Boca has been in the first division without a break since its debut in 1913.
When was Independiente relegated?
On Jun 15, 2013, on the averages, after losing to San Lorenzo. It had spent 101 years in a row in the first division.
Did Racing go down?
Yes, in 1983, after 73 seasons in a row in the first division. It played 1984 and 1985 in the second division.
And San Lorenzo?
It was the first of the big clubs to go down, in 1981. It played 1982 in the second division and came back for 1983.