Once convicted of a crime, a defendant typically has thirty days from the time of sentencing to file a "Notice of Appeal."  Unlike civil cases, in which either the plaintiff or the defendant may appeal an unfavorable judgment, only the defense may appeal a conviction.  No matter how much the prosecution is aggrieved by an acquittal, it may not appeal a verdict in which the accused was found "not guilty."

If the appeal is noted in a timely manner, parties may not use this process to try their case all over again. In most cases, appeals are heard "on the record" by the appellate court’s review of a transcript of the trial proceedings, briefs submitted by the attorneys, and oral arguments focusing on the law surrounding the case. On appeal, defendants must do much more than express disagreement with unfavorable verdicts. Instead, these appellants must show that the trial judge committed some type of legal error which produced these adverse results, or that prosecutorial misconduct contributed to the unfavorable outcome. If persuaded, the appellate court may remand the case for a new trial or, in some instances, even reverse a conviction that might not stand under legal principles articulated in the appellate opinion.

Even if the conviction is affirmed on appeal, and the defendant is incarcerated, many prisoners seek a form of "post-conviction" relief by filing a Petition for Writ of Habeas Corpus.  In these civil proceedings, a prisoner essentially tries to escape from jail ... legally.  Arguing that they are being imprisoned in violation of their federal constitutional rights, inmates seeking a writ of habeas corpus often claim that the process by which they were convicted failed to safeguard such fundamental rights as the right to effective assistance of counsel, the right to a fair trial, and the right to confront one's accusers.  Though it is not supposed to enable an accused to relitigate his case, critics of this procedure argue that it gives defendants a second opportunity to protest his conviction by raising a host of arguments that could have been addressed at the time of trial.  This is particularly true in capital cases, where those on death row may raise new issues for decades, as court-appointed lawyers not only appeal the conviction itself, but seek habeas relief in both state and federal courts.