Occupational Title | Brief Number | HOC Code |
| Ice Cream Mix Processing Operators (dairy products manufacturing) | 173 | REI |
| Illuminating Engineers | 356 | IRE |
| Illustrators (cartoonists) | 124 | AER |
| Illustrators, Editorial (cartoonists) | 124 | AER |
| Illustrators (fine artists) | 653 | AER |
| Illustrators, Medical | 289 | AIE |
| Illustrators (publishing) | 231 | AER, ARS, CIR, CRA |
| Illustrators, Technical | 287 | ARI |
| Image Consultants | 625 | ASE, ASR, IER, SEA |
| Image Intelligence Workers | 626 | AES, ERS |
| Immigration Enforcement Agents | 139 | no code |
| Immigration Enforcement Officers | 139 | SER |
| Immigration Information Officers (citizenship & immigration) | 105 | ECS, ESA |
| Immigration Services Officer | 105 | no code |
| Immunodermatologists | 527 | ISR |
| Immunologists | 353 | ISE |
| Immunologists (biotechnologists) | 634 | IRE |
| Impersonators (variety performers) | 607 | AES |
| Import-Export Agents | 403 | SEC |
| Independent Claim Adjusters | 300 | ESR |
| Individual Carriers (publishing) | 231 | RES |
| Industrial Archaeologists | 343 | IRE |
| Industrial Cafeteria Supervisors | 33 | ESR |
| Industrial Chemicals Production Workers | 369 | no code |
| Industrial Designers | 126 | AES |
| Industrial Economists | 233 | IAS |
| Industrial Engineers | 284 | EIR |
| Industrial Health Engineers (safety professionals) | 420 | EIC |
| Industrial Hygiene Chemists | 461 | IRE |
| Industrial Hygiene Engineers | 461 | EIC |
| Industrial Hygienists | 461 | IRE |
| Industrial Hygienists (safety professionals) | 420 | EIC |
| Industrial Machinery Mechanics | 315 | RIC |
| Industrial-Organizational Psychologists | 144 | IES |
| Industrial Photographers | 12 | ARS |
| Industrial Relations Directors (human resources managers) | 258 | ESI |
| Industrial Sociologists | 316 | IES |
| Industrial Traffic Managers | 115 | ESR |
| Infant Nurses (child care workers) | 604 | SAE |
| Inflated Ball Molders (sporting goods production) | 567 | RES |
| Information Clerks (office) | 3 | ECS |
| Information Clerks (receptionists) | 107 | CSE |
| Information Officers | 189 | ESA |
| Information Scientists (librarians) | 82 | IER |
| Information Specialists (association executives) | 549 | IER |
| Information Systems Auditors | 101 | CIS |
| Information Systems Managers | 77 | SEI |
| Ingot Headers (iron & steel industry) | 305 | RCS |
| Inorganic Chemists | 153 | IRE |
| Input Operators | 308 | CSE |
| Inspectors (apparel industry) | 35 | CRE |
| Inspectors (canning & preserving) | 389 | REC |
| Inspectors (confectionary industry) | 357 | CRS |
| Inspectors (dry cleaning) | 34 | CSR |
| Inspectors (electrical and electronics industry) | 318 | CRS |
| Inspectors, Fill (canning & preserving) | 389 | REI |
| Inspectors (fireworks industry) | 553 | RCS |
| Inspectors (motor vehicle & parts manufacturing) | 376 | REI |
| Inspectors (petroleum refining) | 188 | RSC |
| Inspectors (pharmaceutical industry) | 306 | CER, RCI |
| Inspectors (pottery & porcelain ware industry) | 137 | CSR, RCI, REI |
| Inspectors (shoe industry) | 142 | RIE |
| Inspectors (slaughtering & meat-packing production) | 423 | REI |
| Inspectors, Testers, Sorters, Samplers, and Weighers (aerospace) | 509 | RIC, RIE |
| Inspectors (winery workers) | 613 | CRE |
| Instructional Aides | 292 | SCE |
| Instructional Coordinators | 368 | SAE |
| Instructors (college & university faculty members) | 184 | SEI |
| Instrumental Musicians | 80 | ASC |
| Instrumentation Chemists | 153 | IRC |
| Instrumentation Technicians | 194 | RIC |
| Insulation Workers | 383 | RCI |
| Insurance Claim Adjusters | 300 | ESR |
| Insurance Claim Examiners (adjusters) | 300 | ESR |
| Insurance Investigators | 300 | ESR |
| Insurance Sales Agents | 218 | ESC |
| Insurance Underwriters | 615 | CSE |
| Intelligence Officers | 626 | AES, ERS |
| Intercity Bus Drivers | 52 | RES |
| Intercity Drivers (truck) | 42 | RIE |
| Interior Designers | 30 | AES |
| Internal Auditors | 101 | ICR |
| Internal Auditors (accountants) | 63 | ICR |
| International Operations Officers (citizenship & immigration) | 105 | ECS, ESA |
| International Trade Economists | 233 | IAS |
| Internet Site Developers (publishing) | 231 | IRS |
| Internists, General | 686 | IRS |
| Interpreters, Oral | 365 | SCE |
| Interpreters, Sign Language | 365 | SCE |
| Interpreters (translators) | 28 | ESA |
| Interpretive Rangers | 120 | ESR |
| Interstate Drivers (truck) | 42 | RIE |
| Interventional Radiologists | 462 | IRS |
| Interviewers | 214 | no code |
| Interviewers, Employment | 402 | SCE |
| Interviewers (marketing researchers) | 254 | CSE |
| Interviewers, Survey (public opinion researchers) | 583 | CSE |
| Inventory Clerks (stock) | 108 | RCI |
| Investigators, Fire (fire fighters) | 69 | IER |
| Investigators, Narcotics (police detectives) | 44 | SRE |
| Investigators, Police | 44 | SER |
| Investigators, Private | 562 | ESI |
| Investment Bankers | 433 | ESC |
| Investment Bankers (financial planners) | 597 | ESC |
| Investors | 550 | ESI, ESR |
| Ion-Exchange Operators (cosmetics industry) | 622 | RSC |
| Iron and Steel Industry Workers | 305 | no code |
| Ironworkers, Construction | 359 | REI |
| Ironworkers, Ornamental (construction) | 359 | RIS |
| Ironworkers, Reinforcing (construction) | 359 | RES |
| Ironworkers, Structural | 359 | REI |