After guiding the club to a 13th-placed finish in 2008–09, Brendan Rodgers resigned as manager of Watford in June 2009 to take up the same role at Reading, with three members of his coaching staff doing likewise.

Previous manager Aidy Boothroyd left the club by "mutual consent"[2] in November 2008 and was replaced by former Reading and Chelsea academy boss Brendan Rodgers.

[3] The only player to leave the club prior to the start of pre-season training was Lee Williamson, who had spent the second half of the 2008–09 season on loan at Preston.

[5] The first team began with friendly matches at local sides Boreham Wood, Hampton & Richmond and Wealdstone, before a pre-season tour to Spain where they faced CF Balaguer and UE Lleida.

The provisional fixture list was released on 17 June 2009, but was subject to change in the event of clashes with other competitions, inclement weather, or matches being selected for television coverage.

[16] Watford's home games against Sheffield Wednesday and QPR were played on a Friday and Monday respectively, as a result of live television coverage.

[17] The home game against Sheffield United was postponed and rescheduled due to adverse weather conditions, while the away fixture at Blackpool was brought forward from a Tuesday to the preceding Saturday, as both clubs were eliminated from the FA Cup in the third round.

Scott Severin was playing his first competitive match for Watford, and fellow debutant Danny Graham scored the opening goal after 27 minutes, a close range finish from a Tommy Smith cross.

His and Cleverley's goals were equalised by Alex Baptiste and Gary Taylor-Fletcher respectively, giving Blackpool their fourth consecutive draw.

The departures of Smith, Williamson and McAnuff meant that Lansbury and Marvin Sordell made their first starts, and helped Hodson retain his place in the team.

Graham nutmegged goalkeeper Dorus de Vries to put Watford ahead, but Swansea defender Alan Tate scored a late header to salvage a 1–1 draw.

Captain Jay DeMerit suffered an injury whilst on international duty with the USA, and was replaced by Dale Bennett, who made his Football League debut.

With Watford trailing 2–0 at half time, Mackay changed from a 4–5–1 formation to a 4–4–2, with striker Helguson replacing attacking midfielder Henri Lansbury.

[32] Former Watford player Grzegorz Rasiak scored Reading's goal, in a match that also saw Jobi McAnuff and Brynjar Gunnarsson facing their former club.

[37] They responded with a home win over Preston in their next match, with Cleverley scoring to join Danny Graham as the club's leading goalscorer of the season.

Despite the absence of Chelsea's top scorers Didier Drogba and Nicolas Anelka, Watford conceded five goals without reply, and were eliminated from the competition.

Watford signed three permanent players before the first game of the season: former Scotland international Scott Severin, Carlisle United striker Danny Graham, and Slovenian left back Jure Travner.

The club took this opportunity to sign Scotland under-21 international Stephen McGinn, young Rochdale winger Will Buckley, and 30-year-old centre back Martin Taylor.

"[97] After the early departures of Theo Robinson and Al Bangura, Tamás Priskin was sold to Ipswich Town in the first week of August, just before the start of the Championship season.

Other players acquired in this manner included his Manchester United teammate Craig Cathcart, and Arsenal midfielder Henri Lansbury.

The Iceland international made an instant impact on his return to Vicarage Road, scoring two goals as a substitute in a 3–3 draw against Leicester City.

For similar reasons to their young acquisitions, Watford loaned players such as O'Toole, Billy Gibson and Marvin Sordell to lower-league sides, in the hope that they would gain first-team experience.

He toured the United States with Northern Ireland, making his international debut as a substitute against Turkey and four days later starting for his country against World Cup qualifiers Chile.

Loan duo Tom Cleverley and Henri Lansbury played alongside goalkeeper Scott Loach in England under-21s UEFA Euro 2011 qualifying campaign.

[129] Watford's reserves competed in the Football Combination East Division, and played their home matches at Boreham Wood's stadium, Meadow Park.

Other teams in the league included Watford's historic rivals Luton Town and fellow Hertfordshire side Stevenage Borough.

[135] A total of 14 players appeared for both the senior and reserve teams in 2009–10, including Henderson, Lee Hodson, Dale Bennett and Michael Bryan.

The match attracted 3,389 Watford fans, and ended in a 1–1 draw, with ex-Watford player Grzegorz Rasiak scoring Reading's goal, and Jobi McAnuff and Brynjar Gunnarsson also playing a part.

Upon announcing the loan, Watford revealed that this finance would only be sufficient to cover the club's costs until 22 December, and that a further £5.5 million would be needed to keep the business afloat until 30 June 2010.

The club received an offer from Fordwat to underwrite a rights issue worth £7.5m, but revealed that for this plan to work VGS would have to agree to suspend the loan repayment, indicating that they would be placed into administration unless agreement were reached.