Zibrant's managing director for sales and marketing Fay Sharpe topped the annual Power 50 index after a successful year, which saw the agency win new business from clients including Shell and BMW.
The agency also employed almost 100 new staff in 2010 and has recently won a major deal with Pfizer for the pharmaceutical company's congress work.
"Last year was Zibrant's best year and it was absolutely incredible to be part of that," said Sharpe, who was last year ranked at number eight.
"I need to thank my business partner Chris Parnham, who is an absolute inspiration to work with, my sales and marketing team, who are creative, passionate and enthusiastic, and everyone at Zibrant, who make it a pleasure for me to do my job.
"Thank you to C&IT magazine and its readers for voting for me. I am the first woman to have won so go girl power. I feel very proud and honoured."
The Power 50 was unveiled at C&IT's venue partner The Century Club in Shaftesbury Avenue last night and included a total of 17 new entries.
Among those was Expotel's chief executive Ian Burnley, who jumped straight into second place in the Power 50.
Zibrant's managing director of operations Chris Parnham made the number five place, up from 23 last year.
The full Power 50 list:
1 Fay Sharpe, managing director – sales and marketing, Zibrant
2 Ian Burnley, chief executive, Expotel
3 Zanine Adams, head of event solutions and UK sales, Visit London
4 Nick Bender, managing director, Grass Roots Eventcom
5 Chris Parnham, managing director – operations, Zibrant
6 Aileen Reuter, marketing director, Grass Roots
7 Kate Conway, events manager, Tesco
8 Nick Porter, managing director, Fresh Group
9 David Taylor, sales director, Grass Roots, HBI
10 Anita Lowe, chief executive, Venues Event Management
11 Nigel Cooper, divisional managing director travel and events, Motivcom
12 Julie Besbrode, group chief executive, Fresh Approach UK
13 Des McLaughlin, managing director, Grass Roots, HBI
14 Leigh Jagger, CEO, Banks Sadler
15 Simon Hughes, director of live events, COI
16 Rob Davidson, senior lecturer in events management, University of Greenwich
17 Matt Smith, director, Black Tomato
18 Jackie Boughton, head of sales, Wembley Stadium
19 Tina Morris, managing partner, Adding Value
20 Hamish Reid, general manager, Jersey Conference Bureau
21 Janine Glasspole, director, GP Associates
22 Maria Duddin, general manager, The Brewery
23 Andrew Gilkerson, European procurement manager, Pfizer
24 Kevin Murphy, chief executive, ICC London Excel
25 Samantha van Leeuwen, head of UK hotels and venues, PricewaterhouseCoopers
26 Sam Wilson, director, ECO Events
27 Jayson Weston, events manager, Indesit
28 Joy Thomas, director, corporate events, FICO
29 Jennifer Jenkins, managing director, MCI UK
30 Peter Kerwood, marketing director, Altitude London
31 Dale Parmenter, managing director, DRP
32 Guy Bigwood, group sustainability director, MCI
33 Matt Edgcumbe, managing director, Powwow
34 Peter Ducker, executive director, HBAA
35 Chloe Ward, head of corporate, RPM
36 Randle Stonier, founding partner, Adding Value
37 Mark Taylor, head of events, BI Worldwide
38 Cath Couzens, director, Perception Sales & Marketing
39 David Hornby, director, Why Not
40 Duncan Beale, managing director, Line Up
41 Fiona Pelham, managing director, Sustainable Events / President MPI
42 Paul Hussey, director of business development, BSI
43 Claudia Schuitemaker, director, Hotel Republic
44 Mark Saxby, sales and marketing director, Universal World Events
45 Samme Allen, President elect, MPI UK
46 Sarah Wright, event director, Benchmark Sport Holdings
47 Julian Pullan, president, EMEA, Jack Morton Worldwide
48 Ian Irving, director, Experience This
49 Louise Davies, events director, Seventeen Events
50 Kate Harris, head of strategic meetings management, AMEX