Can I fire an employee on the same day he calls in sick?

You should consult with a Texas attorney to review your situation in consideration of Texas law. When employment is at-will, you can terminate an employee for any reason or no reason whatsoever, so long as it is not based on their membership in a protected classification or their engaging in a protected activity. Additional information may need to be reviewed with an attorney to determine if they would qualify for Family and Medical Leave Act leave for any reason (and whether you are a covered employer). This is most commonly missed when an employee misses work on a Friday and is not scheduled to work until the following Monday. Other considerations you should review would be whether they are missing work due to a workplace injury and you believe they would be claiming workers' compensation. Finally, I would suggest reviewing whether you have any other employees engaging in absenteeism similarly but that you did not discipline. This, in and of itself, would not provide the employee with a claim, but is something you should carefully review before terminating the employee. The money spent in consulting with an attorney now would be well worth it if you prevent a potential lawsuit and verify you are acting legally. Good luck.

I think you are on pretty solid ground based on your documentation and being in an at-will state . . . If he/she is in protected class, or there are other issues which cause you to pause in carrying it through, visit with a Tx employment attorney.

You need to be careful. There may be FMLA and ADA issues in addition I potential protected category issues. We are in Houston and am Board Certified in Labor and Employment Law. 713.742.0900.