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ISA Certified Arborist
The ISA Certified Arborist examination is the core credentialing exam of the International Society of Arboriculture (ISA), a voluntary certification testing a professional's achievement of an industry-accepted standard of knowledge and skill in arboriculture. It is a 200-question multiple-choice written exam (20 of the questions are unscored pretest items) with 3.5 hours (210 minutes) allowed, offered in English, French (Canadian), Traditional Chinese, and Spanish, delivered either paper-based through ISA Certification Partner events or computer-based at Pearson VUE testing centers; the current passing score is 76 percent.
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Questions200 multiple-choice questions (four options each), of which 20 are unidentified unscored pretest questions, leaving 180 scored questions
Testing time3.5 hours (210 minutes)
ScoringCurrent passing score is 76 percent (overall weighted score; subject to change when a new job task analysis is performed); candidates who do not pass must retake the exam until an overall passing score is achieved
Exam feeApplication fee USD 40 for ISA members/credential holders / USD 50 for all others, plus exam enrollment fee USD 295 for ISA members/credential holders / USD 369 for all other candidates (fees independent of exam environment); retake fee USD 120 per attempt; USD 50 reschedule/additional 120-day authorization fee
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Exam overview
What to know before choosing your prep
- Who runs it
- ISA
- Category
- Arboriculture
- Current version
- Examination Outline based on the 2022 Job Task Analysis, administered under the ISA Certified Arborist Program Guide revised August 2025
- Where it applies
- Global
- Exam languages
- English, Spanish, Canadian French, Traditional Chinese
- Testing provider
- Pearson VUE (computer-based exams; Pearson VUE is the grading/testing vendor) and ISA Certification Partner organizations (paper-based exam events)
- Format
- Paper-based exam events sponsored by ISA Certification Partner organizations, or computer-based exams at Pearson VUE testing centers (closed book; reference materials not allowed)
- Availability
- Computer-based candidates receive a 120-day authorization period to schedule and take the exam at a Pearson VUE testing center; paper-based exam events are held on scheduled dates through local ISA Certification Partners
- Results
- Computer-based exams provide result notification immediately upon completion; formal results are posted to the candidate's ISA web account within four weeks of the examination date
Exam structure
Single 3.5-hour, 200-question four-option multiple-choice written exam (20 unscored pretest items). Ten weighted domains from the 2022 Job Task Analysis: Safe Work Practices 15%, Pruning 14%, Tree Biology 11%, Tree Risk 11%, Tree Identification and Selection 9%, Installation and Establishment 9%, Diagnosis and Treatment 9%, Trees and Construction 9%, Soil Management 7%, Urban Forestry 6%
Where rules vary
Worldwide professional certification, not tied to any jurisdiction: exam questions come from "a job task analysis survey filled out by arborists from around the world", exams are sponsored by ISA Certification Partner organizations internationally or offered through Pearson VUE testing centers, and the exam is delivered in English, French (Canadian), Traditional Chinese, and Spanish
Eligibility
Minimum three years of full-time arboriculture experience (one year ≈ 1,795 hours), or education-plus-experience combinations: two-year associate degree with 2 arboriculture courses + 2 years' experience; four-year bachelor degree with 4 arboriculture courses + 1 year; 900 hours assessed training (90 in arboriculture) + 2 years; or 1,800 hours assessed training (180 in arboriculture) + 1 year; approved apprenticeship programs may qualify. Work-experience documentation (and three reference letters if self-employed) required with application
Retake policy
Retake permitted thirty (30) days after the most recent exam attempt, in either environment, with a USD 120 retake fee per attempt; no limit on attempts stated