The Irons defeated Slovenian side NK Domzale 4-2 on aggregate following a 3-0 victory in the first competitive match at their new Olympic Stadium home on Thursday night
After finishing seventh in the Premier League, Slaven Bilic's men will be aiming to join Manchester United and Southampton in the group phase of Europe's second-tier competition
It is the second season in a row that West Ham have been paired with Astra, who knocked them out in the third qualifying round in 2015.
The Romanians had started their European campaign this year in the Champions League qualifiers, but earlier this week lost out to Copenhagen in the third round.
Elsewhere in Friday's draw, Fenerbahce of Turkey were given a tie against Swiss side Grasshoppers while Danish team Brondby tackle Panathinaikos of Greece and Czechs Slavia Prague meet Belgian outfit Anderlecht
The play-offs will be over two legs on August 18 and 25
Source : PA
Source: PA