The following HCEA Top 50 medical meeting list was compiled based on all reported healthcare conventions reported to the Healthcare Convention and Exhibitors Association (HCEA) taking place in 2007 in the United States.  

Ranking Criteria
The top 50 largest medical meetings are ranked by total reported attendance, which is all registered participants at a convention, including exhibitors. In the case of a tie, professional attendance, which is all non-exhibitor attendance, is used to further determine the rank. These meetings are reported for 2007 and include both actual and estimated attendance figures. This is self-reported information provided by the event organizers.

HCEA is a not-for-profit organization representing healthcare convention and exhibition organizers and healthcare exhibitors. HCEA has been collecting medical convention and exhibition data for over 50 years and maintains the world’s largest repository of healthcare convention and exhibit data.

Rank	Association Name	Total Attendance	Professional Attendance
1	Radiological Society Of North America, Inc.	61,980	27,846
2	Greater New York Dental Meeting	60,000	45,000
3	American Dental Association	47,047	37,847
4	Chicago Dental Society	33,762	24,277
5	American Society Of Clinical Oncology	33,700	26,000
6	Society For Neuroscience	32,000	28,000
7	American Academy Of Orthopaedic Surgeons	31,325	14,465
8	American Academy Of Ophthalmology	29,171	18,691
9	California Dental Association - Spring	27,305	22,238
10	American College Of Cardiology	26,184	15,018
11	American Heart Association - Scientific Sessions	25,995	18,391
12	Healthcare Information & Management Systems Society	24,081	n/a
13	Hinman Dental Society	23,152	18,337
14	Biotechnology Industry Organization - International Convention & Exhibition	23,000	n/a
15	Pittsburgh Conference On Analytical Chemistry & Applied Spectroscopy	22,213	n/a
16	Institute Of Food Technologists	22,000	10,000
17	American Society Of Hematology	20,474	16,122
18	Digestive Disease Week	20,435	16,929
19	American Association For Clinical Chemistry	20,000	14,000
20	Clinical Lab Expo	20,000	13,000
21	Medtrade	20,000	12,000
22	American Society Of Anesthesiologists	19,473	11,000
23	American Diabetes Association	18,395	14,195
24	American Academy Of Dermatology	17,000	8,350
25	American Thoracic Society - International Conference	16,000	12,000
26	American Psychological Association	15,210	12,000
27	American Urological Association, Inc.	15,003	8,766
28	Florida International Medical Expo	15,000	n/a
29	Society For Surgery Of The Alimentary Tract	15,000	14,000
30	American Association For Cancer Research	15,000	11,889
31	North American Veterinary Conference	15,000	n/a
32	American Academy Of Family Physicians	14,769	5,261
33	American Chemical Society - Spring National Exposition	14,605	13,331
34	American Public Health Association	14,200	13,500
35	American Chemical Society - Fall National Exposition	14,000	12,000
36	American College Of Rheumatology	14,000	11,000
37	American Society For Pharmacology & Experimental Therapeutics	14,000	n/a
38	American Society Of Nephrology	13,960	11,161
39	Experimental Biology	13,000	12,000
40	Texas Dental Association	13,000	10,000
41	American Society Of Cataract & Refractive Surgery & American Society Of Ophthalmic Administrators	13,000	7,000
42	American College Of Obstetricians & Gynecologists	13,000	4,200
43	American Dietetic Association	13,000	n/a
44	Association Of Perioperative Registered Nurses	12,955	6,261
45	American Academy Of Neurology	12,681	9,496
46	Florida Dental Association	12,000	n/a
47	American Speech-Language-Hearing Association	12,000	10,000
48	Heart Rhythm Society - Scientific Session	12,000	8,000
49	American College Of Surgeons	11,266	6,577
50	American Association Of Critical-Care Nurses	10,881	6,861

2007 HCEA Top 50 Largest U.S. Medical Meetings