diff --git a/mers_lib/src/program/parsed/loop.rs b/mers_lib/src/program/parsed/loop.rs
new file mode 100644
index 0000000..b00c448
--- /dev/null
+++ b/mers_lib/src/program/parsed/loop.rs
@@ -0,0 +1,37 @@
+use crate::{
+    errors::{CheckError, SourceRange},
+    program::{self},
+};
+
+use super::{CompInfo, MersStatement};
+
+#[derive(Debug)]
+pub struct Loop {
+    pub pos_in_src: SourceRange,
+    pub inner: Box<dyn MersStatement>,
+}
+
+impl MersStatement for Loop {
+    fn has_scope(&self) -> bool {
+        true
+    }
+    fn compile_custom(
+        &self,
+        info: &mut crate::info::Info<super::Local>,
+        comp: CompInfo,
+    ) -> Result<Box<dyn program::run::MersStatement>, CheckError> {
+        Ok(Box::new(program::run::r#loop::Loop {
+            pos_in_src: self.pos_in_src.clone(),
+            inner: self.inner.compile(info, comp)?,
+        }))
+    }
+    fn source_range(&self) -> SourceRange {
+        self.pos_in_src.clone()
+    }
+    fn inner_statements(&self) -> Vec<&dyn MersStatement> {
+        vec![self.inner.as_ref()]
+    }
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+}
diff --git a/mers_lib/src/program/run/loop.rs b/mers_lib/src/program/run/loop.rs
new file mode 100644
index 0000000..6750757
--- /dev/null
+++ b/mers_lib/src/program/run/loop.rs
@@ -0,0 +1,69 @@
+use std::sync::Arc;
+
+use crate::{
+    data::{self, Data, Type},
+    errors::{CheckError, SourceRange},
+};
+
+use super::{Info, MersStatement};
+
+#[derive(Debug)]
+pub struct Loop {
+    pub pos_in_src: SourceRange,
+    pub inner: Box<dyn MersStatement>,
+}
+
+impl MersStatement for Loop {
+    fn check_custom(
+        &self,
+        info: &mut super::CheckInfo,
+        init_to: Option<&Type>,
+    ) -> Result<data::Type, CheckError> {
+        if init_to.is_some() {
+            return Err("can't init to statement type If".to_string().into());
+        }
+        let mut t = Type::empty();
+        let inner_return_type = self.inner.check(info, None)?;
+        for i in inner_return_type.types.iter() {
+            if let Some(i) = i.as_any().downcast_ref::<data::tuple::TupleT>() {
+                if i.0.len() > 1 {
+                    return Err(format!(
+                        "Loop: Inner statement must return ()/(T), not {t} (because of {i}, a tuple of length > 1)."
+                    )
+                    .into());
+                } else {
+                    if let Some(i) = i.0.first() {
+                        for i in i.types.iter() {
+                            t.add(Arc::clone(i));
+                        }
+                    }
+                }
+            } else {
+                return Err(format!(
+                    "Loop: Inner statement must return ()/(T), not {t} (because of {i}, which isn't a tuple)."
+                )
+                .into());
+            }
+        }
+        Ok(t)
+    }
+    fn run_custom(&self, info: &mut Info) -> Data {
+        loop {
+            if let Some(v) = self.inner.run(info).one_tuple_content() {
+                return v;
+            }
+        }
+    }
+    fn has_scope(&self) -> bool {
+        true
+    }
+    fn source_range(&self) -> SourceRange {
+        self.pos_in_src.clone()
+    }
+    fn inner_statements(&self) -> Vec<&dyn MersStatement> {
+        vec![self.inner.as_ref()]
+    }
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+}