Argentine GDP in steepest fall since 2014
The decline was accompanied by a steep fall in exports, after a drought hurt the country's agricultural sector.
The contraction also came amid a currency crisis that has prompted the central bank to raise interest rates to 60% and the government to cut spending.
The country has also requested a bailout from the International Monetary Fund (IMF).
President Mauricio Macri last month asked the IMF to speed up the funding.
He cited in part the deteriorating economy, which has exacerbated the government's financial situation and raised doubts about its ability to meet its financial commitments.
A government official this week predicted that the country's gross domestic product would fall by 2.4% this year.
The 4.2% decline in the April-to-June period followed six consecutive quarters of year-on-year GDP growth, according to the Instituto Nacional de Estadistica y Censos .
It matched a 4.2% contraction in the third quarter of 2014.
Exports dropped by more than 14% from the first three months of the year, Indec's seasonally adjusted figures showed. Private consumption also declined by about 1%.