Our Take
This is a state-level mandate, not an HR trend—payroll systems must hardcode the NICU-then-FMLA sequence or risk treating two distinct leave buckets as one concurrent pool.
Why it matters
Illinois payroll teams and multi-state employers operating there face immediate coding obligations as of June 1. Miscoding unpaid leave or conflating NICU exhaustion with FMLA eligibility exposes the company to wage-and-hour claims and benefit continuity failures.
Do this week
Payroll: audit your leave-tracking system for Illinois employees this week to confirm it codes NICU as a separate, unpaid, sequenced-after-FMLA bucket before the June 1 effective date.
Illinois Mandates Unpaid NICU Leave in Two Employer Tiers
Illinois' Family Neonatal Intensive Care Leave Act took effect June 1, granting job-protected, unpaid leave to employees whose children are in a neonatal intensive care unit (NICU). The law applies only to employers with 16 or more employees.
Coverage splits into two tiers. Employers with 16 to 50 employees must provide up to 10 days of NICU leave. Employers with 51 or more employees must provide up to 20 days. Payroll must first identify which tier applies to the employer before coding any leave request.
The leave itself is unpaid. No automatic wage replacement applies. An employee may elect to substitute accrued paid leave (vacation, sick time), but employers cannot mandate that substitution. If an employee does elect substitution, payroll must apply the correct pay codes and deduct the paid-leave balance.
Employer-sponsored benefits must continue during the leave period. Payroll should confirm with benefits administration how employee premium contributions will be collected while pay is stopped.
NICU Leave Must Stay Separate From FMLA in the Timekeeping System
The law introduces a critical sequencing requirement that many payroll systems do not yet reflect. NICU leave does not run concurrently with the Family and Medical Leave Act (FMLA). Instead, eligible employees must exhaust FMLA first. Only after FMLA runs out does NICU leave begin—and only if the child remains in the NICU.
This means timekeeping and leave-tracking systems cannot treat NICU and FMLA as a single bucket. Systems that run them in parallel risk miscalculating leave balances and inadvertently denying employees the full amount of NICU leave they are entitled to once FMLA expires. For multi-state employers, the mismatch is easy to overlook if the payroll platform defaults to concurrent leave accounting.
Payroll also should ensure that the unpaid status of NICU leave does not automatically trigger a wage-and-hour miscalculation. Leave is unpaid, but benefits and job protection remain in place. Stopping wages without confirming benefits are active can create compliance exposure.
Action Items for Payroll and Benefits Teams
Review your leave-coding schema now. Confirm that your HRIS or payroll system can distinguish NICU leave from FMLA leave and enforces the sequence (FMLA first, then NICU). If your system runs them concurrently by default, flag that for your software vendor or implement a manual control to catch Illinois employees before they file a leave request.
Second, document your benefits-continuation policy during unpaid leave. Confirm with your benefits administrator how premiums will be collected or if the employer is absorbing the cost during the leave period. This avoids late notifications to employees mid-leave.
Third, run a payroll audit for any Illinois employees currently on FMLA or anticipated to take NICU leave. Confirm their leave tier and calculate their remaining balances under the new rule so you can brief them on what NICU leave will be available once FMLA ends.