diff --git a/src/main.rs b/src/main.rs
index e7a429d..22cbfc4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,7 +17,7 @@ async fn run() -> anyhow::Result<()> {
 
     scheduler::reschedule_recurring_tasks(&ctx, &tasks).await?;
 
-    reminder::remind_due_tasks(&ctx, &tasks).await?;
+    reminder::remind_all_tasks(&ctx, &tasks).await?;
 
     Ok(())
 }
diff --git a/src/reminder.rs b/src/reminder.rs
index 6c28026..aba0f3c 100644
--- a/src/reminder.rs
+++ b/src/reminder.rs
@@ -10,7 +10,14 @@ enum BatchingInterval {
     OnTheDay,
 }
 
-pub async fn remind_due_tasks(ctx: &crate::Context, tasks: &[task::Task]) -> anyhow::Result<()> {
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum ReminderType {
+    Basic,
+    Urgent,
+}
+
+pub async fn remind_all_tasks(ctx: &crate::Context, tasks: &[task::Task]) -> anyhow::Result<()> {
+    let mut reminded = 0;
     for task in tasks {
         let Some(due_date) = task.state.due_date_if_open() else {
             continue;
@@ -25,12 +32,139 @@ pub async fn remind_due_tasks(ctx: &crate::Context, tasks: &[task::Task]) -> any
         }
 
         if is_overdue(ctx, due_date) {
-            log::info!("Task {task} is already overdue!");
+            log::debug!("Task {task} is already overdue!");
         }
 
-        log::warn!("TODO: Remind {task}");
+        if let Some((reminded_date, reminder_type)) = check_task_reminded(ctx, task).await? {
+            if reminder_type == ReminderType::Urgent {
+                log::debug!("Was already reminded urgently, skipping.");
+            } else if &reminded_date < due_date && is_overdue(ctx, due_date) {
+                log::info!("Task {task} is now overdue, reminding again urgently...");
+                remind_task(ctx, task, ReminderType::Urgent, batching_interval).await?;
+            } else {
+                log::debug!("Was already reminded, skipping.");
+            }
+            continue;
+        }
+
+        log::info!("Reminding {task} ...");
+        remind_task(ctx, task, ReminderType::Basic, batching_interval).await?;
+        reminded += 1;
     }
 
+    if reminded == 0 {
+        log::info!("No tasks needed to be reminded.");
+    } else {
+        log::debug!("Reminded {reminded} tasks.");
+    }
+
+    Ok(())
+}
+
+const SIGNATURE_BASIC: &'static str = "<small>\\[TaskBot Comment\\]</small>";
+const SIGNATURE_URGENT: &'static str = "<small>\\[TaskBot Comment (Urgent)\\]</small>";
+
+async fn check_task_reminded(
+    ctx: &crate::Context,
+    task: &task::Task,
+) -> anyhow::Result<Option<(jiff::Zoned, ReminderType)>> {
+    let mut timeline = ctx
+        .forgejo
+        .issue_get_comments_and_timeline(
+            &ctx.owner,
+            &ctx.repo,
+            task.issue_number.into(),
+            forgejo_api::structs::IssueGetCommentsAndTimelineQuery {
+                ..Default::default()
+            },
+        )
+        .all()
+        .await
+        .with_context(|| format!("Failed to fetch timeline for {task}"))?;
+
+    // Should not be necessary, but let's be safe.
+    timeline.sort_by_key(|event| event.created_at);
+
+    let mut has_reminder = None;
+    let mut has_urgent_reminder = None;
+    for event in timeline.iter().rev() {
+        match (event.r#type.as_deref(), &event.body) {
+            (Some("reopen"), _) => {
+                // When we find the event where the issue was last reopened, we stop.
+                break;
+            }
+            (Some("comment"), Some(body)) => {
+                if body.contains(SIGNATURE_URGENT) {
+                    log::debug!("Found urgent reminder for issue #{}.", task.issue_number);
+                    has_urgent_reminder = Some(created_at_time(event)?);
+                } else if body.contains(SIGNATURE_BASIC) {
+                    log::debug!("Found reminder for issue #{}.", task.issue_number);
+                    has_reminder = Some(created_at_time(event)?);
+                }
+            }
+            // Ignore all other events.
+            _ => (),
+        }
+    }
+
+    let res = has_urgent_reminder
+        .map(|t| (t, ReminderType::Urgent))
+        .or_else(|| has_reminder.map(|t| (t, ReminderType::Basic)));
+
+    Ok(res)
+}
+
+fn created_at_time(ev: &forgejo_api::structs::TimelineComment) -> anyhow::Result<jiff::Zoned> {
+    Ok(util::time_to_jiff(ev.created_at.with_context(|| {
+        format!("Timeline event {:?} without created_at time", ev.r#type,)
+    })?))
+}
+
+async fn remind_task(
+    ctx: &crate::Context,
+    task: &task::Task,
+    reminder_type: ReminderType,
+    batching_interval: BatchingInterval,
+) -> anyhow::Result<()> {
+    let mut body = match (reminder_type, batching_interval) {
+        (ReminderType::Basic, BatchingInterval::Monthly) => format!(
+            "\
+Beep boop. This task is due this month, go take care of it!"
+        ),
+        (ReminderType::Basic, BatchingInterval::Weekly) => format!(
+            "\
+Beep boop. This task is due this week, go take care of it!"
+        ),
+        (ReminderType::Basic, BatchingInterval::OnTheDay) => format!(
+            "\
+Beep boop. This task is due today, go take care of it!"
+        ),
+        (ReminderType::Urgent, _) => format!(
+            "\
+Hello again. This task is overdue, please take care of it ASAP!"
+        ),
+    };
+
+    let signature = match reminder_type {
+        ReminderType::Basic => SIGNATURE_BASIC,
+        ReminderType::Urgent => SIGNATURE_URGENT,
+    };
+
+    let body = body + "\n\n" + signature;
+
+    ctx.forgejo
+        .issue_create_comment(
+            &ctx.owner,
+            &ctx.repo,
+            task.issue_number.into(),
+            forgejo_api::structs::CreateIssueCommentOption {
+                body: body,
+                updated_at: None,
+            },
+        )
+        .await
+        .with_context(|| format!("Could not create comment to remind task {task}"))?;
+
     Ok(())
 }