Locum Tenens Emergency Medicine: Tax Guide for Shift-Based Assignments

If you've read our broader Locum Tenens Tax Home guide, you already know the core concept: your tax home is the general area of your main place of business, and if you lose it — get reclassified as an itinerant worker with no fixed home base — you lose the ability to deduct any travel expenses at all, because you're never legally "away from home." That risk applies to every traveling physician. For emergency medicine locums specifically, the pattern of the work makes that risk sharper.

Here's why. The IRS's temporary-assignment analysis looks at your work pattern holistically, not just at each individual contract in isolation. A physician who takes one 8-month assignment and returns home has an easy, clean story: one absence, one return. A physician who takes six assignments of two to six weeks each, scattered across the calendar with limited time at home in between, is making the "I have a genuine home base I keep returning to" argument six separate times in the same year — and if the gaps between assignments shrink, or the return trips get shorter and less frequent, the story gets harder to tell convincingly.

More Assignments Means More Chances to Look Itinerant

None of the individual factors change from the general itinerant-worker rules — you still need a permanent residence with real, duplicate expenses, regular return trips, and documented ties to the area. What changes for EM locums is the volume and density of the pattern the IRS is evaluating. A physician with one long contract has to prove their case once a year. An EM locum stacking assignment after assignment, with little downtime between them, has more data points working against a "genuine home base" narrative unless the recordkeeping and actual return trips back it up.

The fix isn't to take fewer assignments — it's to be deliberate about the gaps. Building in even a few days at your tax home between assignments, and making sure those returns show up in your travel records (flight itineraries, mileage logs, credit card activity near your home address), does more to protect your deductions than almost anything else you can do.

Emergency medicine shift work commonly includes premium pay structures: night-shift differentials, holiday premiums, weekend rates, and overtime-style bonuses for picking up extra or last-minute shifts. If you spent any time as a W-2 employee, you may be used to overtime having its own rules — time-and-a-half calculations, specific withholding treatment, maybe even a different line on your pay stub.

None of that carries over to 1099 locum work. When a staffing agency or facility pays you as an independent contractor, every dollar on your settlement statement or 1099-NEC — base shift rate, night differential, holiday premium, whatever it's labeled — is simply gross self-employment income. There is no separate tax category, no special rate, and no different withholding rule for the "extra" pay versus the "regular" pay. It all gets added together, reported on Schedule C, and taxed the same way: ordinary income tax at your marginal rate, plus self-employment tax.

Why This Matters for Quarterly Estimates

Because premium pay isn't broken out or taxed differently, it still has to be folded into your running income total for the purposes of calculating quarterly estimated tax payments. EM locums who pick up a heavy run of night shifts or holiday coverage in one quarter — common in EM, since facilities often pay a premium specifically to fill those gaps — can see a real income spike in that quarter that needs to be reflected in the next estimated payment. Under-estimating because "that was just overtime, not my real pay" is a common and avoidable mistake.

Working six assignments across four states in one year doesn't just mean four state tax returns at filing time — it means four separate sets of rules about when income was earned, what the nonresident filing threshold is, whether reciprocity agreements apply, and how much to withhold or pay in estimates to each state along the way. Getting this wrong doesn't just risk a bigger bill in April; it risks penalties in the states you underpaid throughout the year.

What Records to Keep for Each Assignment

For every assignment, from the day you accept the contract through your final shift, keep:

• The signed contract — showing the facility, state, and the expected (temporary) duration
• A day-by-day log of physical presence — which days you actually worked or were physically in that state, not just the contract dates
• Gross pay by state — a running total of income sourced to each state as you're paid, not reconstructed later
• Travel dates to and from the assignment — flights, drives, and especially any return trips to your tax home in between
• Lodging receipts at the assignment location — supports both the travel deduction and the "this was temporary" narrative

A Practical System

Most EM locums who stay organized use some version of a simple running spreadsheet: one row per assignment, with columns for state, facility, start date, end date, days physically present, gross pay, and a checkbox for whether a nonresident return is expected to be required. Updated as you go, this single document does most of the heavy lifting at tax time — instead of reconstructing a year of scattered assignments from memory, your preparer is just formatting what you've already tracked.

Illustrative example, not a specific client outcome. Dr. Reyes is an emergency medicine physician whose tax home is a rented apartment in Texas (no state income tax), where she returns between assignments and maintains a lease, vehicle registration, and voter registration. Over the year, she works six separate locum assignments:

Total gross 1099 income across all six assignments: $243,500. Because Dr. Reyes returned to her Texas apartment between every assignment (documented with flight records and a day-by-day calendar), maintained continuous lease payments the entire year, and kept each individual assignment under the one-year "temporary" threshold, her travel expenses — airfare, lodging at each assignment, rental cars, and per diem meals — remain fully deductible.